High frequency line-to-waveguide converter and high frequency package

ABSTRACT

A high frequency line-waveguide converter comprises a high frequency line including a dielectric layer, a line conductor disposed on an upper surface of the dielectric layer, and a ground conductor layer disposed on the same surface so as to surround one end of the line conductor, a slot formed in the ground conductor layer so as to be substantially orthogonal to the one end of the line conductor and coupled to the line conductor, a shield conductor part disposed on a side of or in an inside of the dielectric layer so as to surround the one end of the line conductor and the slot, and a waveguide disposed at the lower side of the dielectric layer so that an opening is made opposite to the one end of the line conductor and the slot, and electrically connected to the shield conductor part.

CROSS-REFERENCE TO THE RELATED APPLICATIONS

This is a divisional of application Ser. No. 10/696,745 filed Oct. 29,2003, the entire contents of which are incorporated by reference. Thisapplication also claims benefit of priority under 35 USC § 119 toJapanese Patent Application No. 2002-314410 filed Oct. 29, 2002 andJapanese Patent Application No. 2003-087350 filed Mar. 27, 2003, theentire contents of both of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a high frequency line-to-waveguideconverter in which a high frequency line, such as a coplanar line or acoplanar line having ground, forming a high frequency circuit and usedin a microwave or millimeter wave region is converted into a waveguide,and connection between the high frequency circuit and an antenna orbetween high frequency circuits is performed through the waveguide, sothat mounting of a system can be easily performed.

Besides, the invention relates to a high frequency package for easilyconnecting a high frequency electronic component used in a microwave ormillimeter wave region to a waveguide.

2. Description of the Related Art

In recent years, we enter the advanced information age, and with respectto a high frequency signal used for information transmission, studieshave been carried out to utilize frequencies in the range from amicrowave of 1 to 30 GHz to a millimeter wave of 30 to 300 GHz, and anapplication system using a high frequency signal of a millimeter wave,such as an inter-vehicular radar, is also proposed.

In such a high frequency system, there is a problem that since thefrequency of a high frequency signal is high, the attenuation of thehigh frequency signal in a high frequency line constituting a circuitbecomes large. For example, in the case where the high frequency linehas a microstrip line structure, dielectric loss in a dielectricsubstrate becomes large in proportion to a frequency (when dielectricloss tangent is independent of a frequency), and conductor loss in theline conductor becomes large in proportion to a square root of thefrequency. From this, even when the same microstrip line is used, whenthe frequency to be used becomes high from 1 GHz to 10 GHz, thedielectric loss becomes 10 times as high, and the conductor loss becomesabout 3.2 times as high, and there is a problem that in order tocompensate the loss, it becomes necessary to heavily use expensive highfrequency components having low noise, high efficiency and high gain,and the system becomes expensive.

It is known that as compared with the high frequency line of themicrostrip line structure as stated above, the transmission loss of ahigh frequency signal in a waveguide is low. For example, the loss of awaveguide WR-28 used in a band of 26 GHz to 40 GHz is about 0.005 dB/cmat 40 GHz, and this is remarkably smaller than the loss of about 1 dB/cmof the microstrip line using an aluminum substrate. This is because ascompared with the normal high frequency line (generally designed to havean impedance of 50Ω) by the microstrip line or the like, the impedanceof the waveguide is high (although changed according to the frequency,it is designed to be of the order of approximately 500Ω), and in thenormal high frequency line, although the contribution of electric fieldenergy transmitted in the dielectric substance is large in relation tothe transmitted signal energy, the waveguide has such a structure thatair having a dielectric loss tangent of almost 0 is used as thedielectric substance, a current flowing through the wall of thewaveguide, which causes relatively low magnetic energy, may be small,and since the current flows through a relatively wide area of the wallof the waveguide, electric resistance becomes small and the conductorloss becomes small.

Besides, waveguides are generally connected to each other by screws.Thus, attachment and detachment can be easily performed. For example,when the waveguide is used for the connection of a high frequencycircuit module and an antenna, their respective waveguide ports are usedto carry out their respective checks before assembly, and a highfrequency front end can be assembled by combining good components witheach other, and the manufacture yield can be raised. From these, thefront end using the waveguide is conventionally often adopted fortransmission between the high frequency circuit module and the antenna,in which a transmission distance often becomes long.

FIG. 14 is a sectional view for explaining a structure of such a highfrequency front end. According to FIG. 14, a front end 10 is constructedsuch that a module 11 and an antenna 12 are connected through awaveguide member 13. The module 11 is mounted on a metal chassis 15having a waveguide opening 14. Besides, in this front end 10, there isconstructed a high frequency line-to-waveguide converter 18 including amicrostrip substrate 16 in which a microstrip line as a high frequencyline is formed and a waveguide constituted by the waveguide opening 14and a short circuit termination member 17. A wiring substrate 19 onwhich a high frequency component is mounted is connected to themicrostrip line of the microstrip substrate 16 by wire bonding.

The high frequency line-to-waveguide converter 18 in this front end 10is of the type in which at a position apart from the short circuittermination surface of the short circuit termination member 17 by adistance of ¼ of a wavelength (guide wavelength), in the waveguide, ofan electromagnetic wave excited by a high frequency signal, a probe (aportion where although a line conductor is extended, a ground conductoris not formed) formed on the microstrip substrate 16 is inserted fromthe side of the waveguide by a length of approximately ¼ of a signalwavelength. This probe functions as an antenna in the waveguide, andradiates a high frequency signal as an electromagnetic wave into thewaveguide. The half of the electromagnetic wave radiated into thewaveguide is directly transmitted to the lower waveguide member 13, andthe remaining half is transmitted toward the upper short circuittermination member 17. The phase of the electromagnetic wave transmittedtoward the short circuit termination member 17 is inverted at the shortcircuit termination surface and is totally reflected. The totallyreflected electromagnetic wave is returned to the probe portion, and iscombined with the electromagnetic wave directly radiated downward fromthe probe. At this time, when the distance between the probe and theshort circuit termination surface is made ¼ of the guide wavelength, thelength of the both way optical path starting from the probe andreturning to the probe via the short circuit termination surface becomesthe ½ wavelength, and the phase of the electromagnetic wave reflected atthe short circuit termination surface becomes opposite to that of theelectromagnetic wave directly radiated from the probe by the opticalpath difference. Eventually, the phase of the electromagnetic wavereflected at the short circuit termination surface is inverted when itis reflected at the short circuit termination surface, and further, thephase is reversed by the optical path difference, and becomes the sameas the phase of the electromagnetic wave directly radiated downward fromthe probe, and the electromagnetic wave is transmitted to the lowerwaveguide member 13.

At this time, in order to cause the probe to function as the antenna,the length of the probe inserted into the waveguide is required to bemade exactly ¼ of the wavelength of the transmission line. Besides, inorder to cause the phase of the electromagnetic wave radiated from theprobe upward and reflected at the short circuit termination surface tobecome the same phase as the phase of the electromagnetic wave radiateddownward from the probe, the distance between the probe and the shortcircuit termination surface is required to be made exactly ¼ of theguide wavelength. Accordingly, the characteristic is greatly changed bythe insertion position of the microstrip substrate 16, which functionsas the antenna, into the waveguide, and the relation between theposition of the microstrip substrate 16 and the position of the shortcircuit termination surface of the short circuit termination member 17.

Since the high frequency line-to-waveguide converter 18, together withthe wiring substrate 19, is constructed on the metal chassis 15 byassembly, there is a problem that in the case where conversion loss ofthe high frequency line-to-waveguide converter becomes large by positionshift of the respective members, the assembly becomes poor, and all ofthe used members become wasteful. Besides, the related art is disclosedin WO96/27913 and Japanese Unexamined Patent Publication JP-A2001-177312 (2001).

FIG. 15 is a sectional view for explaining a structure of a highfrequency line-to-waveguide converter. According to FIG. 15, a front end20 is constructed such that a high frequency package 21 is connected toan antenna 22 through a waveguide 23. The high frequency package 21 isconstructed such that a conversion substrate 26 having a built-inwaveguide converter 25 is joined to a metal base 24. The waveguideconverter 25 converts a plane circuit 28 for transmitting a highfrequency signal processed by a high frequency electronic component 27mounted on the high frequency package 21 into a waveguide mode 31through a slot 30 formed in a ground layer 29 in the inside of theconversion substrate 26.

In this high frequency package 21, it is necessary to provide the areafor mounting of the high frequency electronic component 27, togetherwith the waveguide converter 25, in the conversion substrate 26, andthere is a problem that in the case where the number of parts of thehigh frequency electronic component 27 is increased, the size becomeslarge, and warp or fracture can occur due to the mismatch in thermalexpansion between the conversion substrate 26 and the metal base 24 atthe time of assembly of the package. Besides, the related art isdisclosed in U.S. Pat. No. 6,239,669.

In order to solve the problem as stated above, for example, WO96/27913proposes a microstrip-waveguide transition including a microstrip lineformed on an upper surface of a dielectric substrate and a slot formedin a lower ground conductor layer and functioning as an antenna. In themicrostrip-waveguide transition proposed by WO96/27913, the thickness ofthe dielectric substance from the slot to a waveguide is made ¼ of asignal wavelength of a high frequency signal. This is such that adifference in impedance between the slot and the waveguide is adjustedby a ¼ wavelength matching device of the dielectric substance.

According to this structure, an electromagnetic wave radiated from theslot and reflected at a boundary between the matching device of thedielectric substance and the waveguide is reflected at the groundconductor layer in which the slot is formed, and is again returned tothe boundary between the matching device and the waveguide. At thistime, when the thickness of the matching device is made ¼ of the signalwavelength, an optical path difference between the electromagnetic wave(reflected wave), which is reflected at the boundary and is againreturned, and the electromagnetic wave (direct wave) directlytransmitted from the slot to the boundary becomes ½ of the signalwavelength, and the phase is inverted when the reflected wave isreflected at the ground conductor layer, and accordingly, the directwave and the reflected wave have the same phase at the boundary tointensify each other, and are transmitted to the waveguide.

According to this conversion structure, although the conversioncharacteristic is greatly changed by the thickness of the matchingdevice, in this case, since the matching device is integrallyconstructed in the dielectric substrate, it becomes possible to lessenvariation in the thickness of the dielectric substance, and variation inthe conversion characteristic can be made small. Besides, when thedielectric substrate at the microstrip side is covered with a cap, italso becomes possible to airtightly seal the microstrip side at the sametime as the conversion into the waveguide.

In this structure, electromagnetic coupling between different layers isused for coupling of the high frequency line and the slot. Thiselectromagnetic coupling, together with the foregoing matching device,plays a main role in the conversion operation. However, thecharacteristic of the electromagnetic coupling is changed by the size ofthe slot and the length of a stub (a portion where the high frequencyline protrudes from the slot), that is, the relative positional relationbetween the high frequency line and the slot. Accordingly, in thisstructure, the conversion characteristic is greatly changed by the sizeof the slot and the length of the stub, and since the high frequencyline and the slot are disposed in the different layers, there is aproblem that the length of the stub determined from the relativepositional relation between both is apt to vary, and the conversioncharacteristic is apt to change.

Besides, in this structure, since the slot is placed in the inside ofthe dielectric substrate, there is a problem that it is difficult tocheck the length of the slot, the width of the slot, and the length ofthe stub from the outside, and it is also difficult to stabilize thecharacteristic by making a check.

In order to solve the problem as stated above, for example, a highfrequency line-to-waveguide converter is conceivable in which a slotfunctioning as an antenna is formed at a tip of a coplanar line on asurface of a dielectric substrate, a waveguide is connected to a rearsurface of the dielectric substrate at a position opposite to the slot,and a shield conductor part for connecting the waveguide and a groundconductor layer of the coplanar line is provided along an opening of thewaveguide. The coplanar line is constituted by a line conductor andground conductor layers disposed at both sides thereof, and the groundconductor layers in this case function as the ground of the coplanarline, and further function also as reflecting plates for againreflecting an electromagnetic wave (reflected wave) radiated from theslot, reflected at the boundary between the dielectric substrate and thewaveguide and returned to the slot side. According to this converter,when the distance from the slot to the boundary between the dielectricsubstrate and the waveguide is set to ¼ of the wavelength of theelectromagnetic wave transmitted through the dielectric layer, anoptical path difference between the reflected wave, which is radiatedfrom the slot, is reflected at the boundary between the dielectricsubstrate and the waveguide, is again reflected at the ground conductorlayer and reaches the boundary, and the electromagnetic wave (directwave) directly transmitted to the boundary from the slot becomes equalto ½ of the wavelength of the electromagnetic wave, and the phase of themagnetic field of the reflected wave is inverted when it is reflected atthe boundary between the dielectric substrate and the waveguide, andaccordingly, the direct wave and the reflected wave have the same phaseat the boundary to intensify each other, and are transmitted to thewaveguide. That is, the dielectric substrate intervening between theslot and the waveguide and having the thickness set to ¼ of thewavelength of the electromagnetic wave functions as a matching device ofthe slot and the waveguide whose impedances are different from eachother.

However, in this structure, since the coplanar line is in contact withthe matching device of the dielectric substrate, part of theelectromagnetic wave of the signal transmitted through the coplanar lineis distributed in the matching device, and this generates an unnecessaryelectromagnetic wave distribution (here, called a mode) in the matchingdevice, and there is a fear that the transmission of the high frequencysignal to the waveguide is impeded. For example, immediately under theline conductor of the coplanar line, the magnetic field by the signalbecomes parallel to the surface of the dielectric substrate. Thismagnetic field excites a TM mode as a resonant mode at the time when thematching device is made the dielectric waveguide, and the signal energyof a TE mode as a transmission mode shifts to the TM mode and resonates,and the signal is reflected, and accordingly, there is a case where theconversion into the waveguide can not be excellently performed.

In order to solve the problem as stated above, it is conceivable thatfor example, the conversion substrate 26 including only the waveguideconverter 25 is fabricated, and is connected to the metal base 24. Bydoing so, it becomes possible to lessen the conversion substrate 26, theresidual stress after the assembly due to the mismatch in thermalexpansion between the conversion substrate 26 and the metal base 24becomes low, and it is possible to prevent the warp or fracture of thehigh frequency package 21.

However, in this structure, when the upper surface of the conversionboard 26 and the upper surface of the high frequency electroniccomponent 27 are made the same surface, although the respective signallines can be connected by wire bonding or ribbon bonding at a relativelyshort distance, since the thickness of the conversion substrate 26including the waveguide converter 25 is generally overwhelmingly thickerthan the thickness of the high frequency electronic component 27 used inthe microwave or millimeter wave range, a connection distance betweengrounds at the respective lower surfaces becomes longer than aconnection between signal conductors, and there is a case where thephase of the electric potential of the signal conductor deviates fromthe phase of the electric potential of the ground conductor at theconnection part, and the high frequency signal can not be excellentlytransmitted.

SUMMARY OF THE INVENTION

The invention has been made in view of the foregoing problems, and anobject thereof is to provide a high frequency line-to-waveguideconverter which has a high conversion efficiency and a small variationin conversion characteristic.

Another object of the invention is to provide a high frequencyline-to-waveguide converter in which an unnecessary mode does not easilyoccur and a conversion efficiency is high.

Still another object of the invention is to provide a high frequencypackage in which a conversion substrate including only a waveguideconverter 65 is connected to a metal base to prevent a warp or a crackof the high frequency package, and transmission of a high frequencysignal at a connection part between the conversion substrate and a highfrequency electronic component is excellent.

The invention provides a high frequency line-to-waveguide convertercomprising:

a high frequency line including a dielectric layer, a line conductordisposed on one surface of the dielectric layer, and a ground conductorlayer disposed on the same surface so as to surround one end of the lineconductor;

a slot formed in the ground conductor layer so as to be substantiallyorthogonal to the one end of the line conductor and coupled to the highfrequency line;

a shield conductor part disposed on a side of or in an inside of thedielectric layer so as to surround the one end of the line conductor andthe slot; and

a waveguide disposed on a side of the other surface of the dielectriclayer so that an opening is opposite to the one end of the lineconductor and the slot, and electrically connected to the shieldconductor part.

According to the invention, since the high frequency line including theline conductor disposed on the one surface of the dielectric layer andthe ground conductor layer disposed on the same surface so as tosurround the one end of the line conductor is coupled to the slot formedin the ground conductor layer to be substantially orthogonal to the oneend of the line conductor the high frequency line and the slot areformed on the same surface, and as a result, the relative positionalrelation of both is difficult to change, and variation in the length ofa stub as a protruding portion of the high frequency line with respectto the slot can be made small, and accordingly, variation in thecharacteristic of electromagnetic coupling can be made small, andvariation in the conversion characteristic of the high frequencyline-to-waveguide conversion can be made small.

Besides, in the invention it is preferable that the shield conductorpart includes a plurality of shield through conductors disposed in theinside of the dielectric layer.

According to the invention, when the shield conductor part includes theplurality of shield through conductors disposed in the inside of thedielectric layer, at the time of fabrication of the high frequencyline-to-waveguide converter, the shield through conductors can be formedat the same time as the line conductor and the ground conductor layer,and the high frequency line-to-waveguide converter can be easilyfabricated. Besides, since the shape of the region surrounded by theshield through conductors of the dielectric layer can be designedarbitrarily, for example, in the case where an unnecessary resonanceoccurs in the region surrounded by the shield through conductors of thedielectric layer, it becomes possible to shift the unnecessary resonanceto the outside of the band of signal conversion by adjusting thearrangement of the shield conductor part.

Besides, in the invention it is preferable that a thickness of thedielectric layer is approximately (2n−1)/4 (n is a natural number) of awavelength of a signal transmitted through the high frequency line.

According to the invention, when the thickness of the dielectric layeris approximately ¼ of the wavelength of the signal transmitted throughthe high frequency line, a distance from the slot to the boundarybetween the dielectric layer and the waveguide becomes approximately ¼of the signal wavelength, an optical path difference between a reflectedwave, which is radiated from the slot, is reflected at the boundarybetween the dielectric layer and the wave guide, is again reflected atthe ground conductor layer in which the slot is formed, and is againreturned to the boundary and a direct wave directly transmitted from theslot to the boundary becomes ½ of the signal wavelength, and the phaseis inverted when the reflected wave is reflected at the ground conductorlayer, and accordingly, the direct wave and the reflected wave come tohave the same phase at the boundary to intensify each other, and thesignal is efficiently transmitted to the waveguide. At this time, whenthe thickness of the dielectric layer is made (2n−1)/4 of the signalwavelength, where n is a natural number, the optical path differencebetween the reflected wave and the direct wave becomes (n−1)/2 of thesignal wavelength, and since the optical path difference n times as longas the signal wavelength is equivalent to a case where there is nooptical path difference, it substantially becomes ½ of the signalwavelength, and the same effect is obtained.

Besides, according to the invention, when the thickness of thedielectric layer is approximately (2n−1)/4 of the wavelength of thesignal transmitted through the high frequency line, where n is a naturalnumber, the distance from the slot to the boundary between thedielectric layer and the waveguide becomes approximately (2n−1)/4 of thesignal wavelength, and since the length of the optical path in which thereflected wave reflected at the boundary between the dielectric layerand the waveguide is totally reflected at the ground conductor layer andis returned to the boundary becomes substantially ½ of the signalwavelength, the phase becomes inverted when the wave is returned, and incombination with the phase inversion by the total reflection at theground conductor layer, the reflected wave comes to have the same phaseas the direct wave directly transmitted from the slot to the boundary,and these are combined with each other and the signal is efficientlytransmitted to the waveguide. Besides, in addition to that, the signalfrequency becomes high, and the signal wavelength becomes short, and inthe case where the strength of the dielectric layer is lowered when thethickness of the dielectric layer is set to ¼ of the signal wavelength,it becomes possible to suppress the lowering of the strength of thedielectric layer by setting the thickness of the dielectric layer to ¾,5/4 or the like of the signal wavelength.

Besides, in the invention it is preferable that a tip of the one end ofthe line conductor is opened, and a distance between the tip and theslot is approximately (2n−1)/4 (n is a natural number) of the wavelengthof the signal transmitted through the high frequency line.

According to the invention, when the tip of the one end of the lineconductor is opened, and the distance between the tip and the slot isapproximately ¼ of the wavelength of the signal transmitted through thehigh frequency line, the signal (traveling wave) transmitted through thehigh frequency line is totally reflected at the open end, and becomes aregressive wave transmitted in the opposite direction. At this time,since the tip is opened, a current can not flow in the tip, and thecurrent of the regressive wave is reflected in this portion while thephase is inverted to cancel the current of the traveling wave. Thesynthesis of the current of the traveling wave and the current of theregressive wave which inverts the phase produces a standing wave inwhich the open tip is a node and a node pitch is ½ of the signalwavelength. Here, since the distance between the open tip and the slotis ¼ of the signal wavelength, a portion of the high frequency line justabove the slot becomes the antinode of the standing wave, the currentbecomes maximum, and the magnetic field generated by the current becomesmaximum. The magnetic field which becomes maximum moves to the slot,excellent electromagnetic coupling is performed, and the signal isfinally efficiently transmitted to the waveguide. At this time, when thedistance between the open end and the slot is made (2n−1)/4 of thesignal wavelength, where n is a natural number, the slot is positionedat the position of the antinode of the standing wave formed by synthesisof the traveling wave and the regressive wave, and the same effect asthe case where the distance between the open end and the slot is ¼ ofthe signal wavelength is obtained.

Besides, according to the invention, when the tip of the high frequencyline is opened, and the distance between the open tip and the slot isset to (2n−1)/4 of the signal wavelength, where n is a natural number,the standing wave formed by synthesis of the traveling wave transmittedthrough the high frequency line and the regressive wave reflected at theopen tip can be made such that the magnetic field becomes highest at theportion of the slot, and the electromagnetic coupling from the highfrequency line to the slot through the magnetic field is mostexcellently performed, and accordingly, the conversion efficiency of thehigh frequency line-to-waveguide conversion can be made high.

Besides, in the invention it is preferable that a tip of the one end ofthe line conductor is short circuited to the ground conductor layer, anda distance between the tip and the slot is approximately (n−1)/2 (n is anatural number) of the wavelength of the signal transmitted through thehigh frequency line.

According to the invention, when the tip of the one end of the lineconductor is short-circuited to the ground conductor layer, and thedistance between the tip and the slot is approximately ½ of thewavelength of the signal transmitted through the high frequency line,the signal (traveling wave) transmitted through the high frequency lineis totally reflected at the short-circuit end, and becomes theregressive wave transmitted in the opposite direction. At this time,since the tip is short-circuited, a maximum current flows in the tippart, and in this portion, the current of the regressive wave isreflected at the same phase as the current of the traveling wave. Thesynthesis of the current of the traveling wave and the current of theregressive wave which does not change the phase produces a standing wavein which the open tip is an antinode and an antinode pitch is ½ of thesignal wavelength. Here, since the distance between the short-circuittip and the slot is ½ of the signal wavelength, a portion of the highfrequency line just above the slot becomes the antinode of the standingwave, the current becomes maximum, and the magnetic field generated bythe current becomes maximum. The maximum magnetic field moves to theslot, excellent electromagnetic coupling is performed, and the signal isfinally efficiently transmitted to the waveguide. At this time, when thedistance between the short-circuit tip and the slot is made (n−1)/2 ofthe signal wavelength, where n is a natural number, the slot ispositioned at the position of the antinode of the standing wave formedby synthesis of the traveling wave and the regressive wave, and the sameeffect as the case where the distance between the short-circuit tip andthe slot is ½ of the signal wavelength is obtained.

Besides, according to the invention, when the tip of the high frequencyline conductor is short-circuited by the ground conductor layer, and thedistance between the short-circuited tip and the slot is set to (n−1)/2of the signal wavelength, where n is a natural number, the standing waveformed by synthesis of the traveling wave transmitted through the highfrequency line and the regressive wave reflected at the short-circuitedtip can be made such that the magnetic field becomes highest at theportion of the slot, and the electromagnetic coupling from the highfrequency line to the slot through the magnetic field is mostexcellently performed, and accordingly, the conversion efficiency of thehigh frequency line-to-waveguide conversion can be raised.

The invention provides a high frequency line-to-waveguide convertercomprising:

a high frequency line including a dielectric layer, a line conductordisposed on one surface of the dielectric layer, and a same surfaceground conductor layer disposed on the same surface so as to surroundone end of the line conductor;

a slot formed in the same surface ground conductor layer so as to besubstantially orthogonal to the one end of the line conductor andcoupled to the high frequency line in terms of high frequency;

a shield conductor part disposed on a side of or in an inside of thedielectric layer so as to surround the one end of the line conductor andthe slot;

a waveguide disposed on a side of the other surface of the dielectriclayer so that an opening is opposite to the one end of the lineconductor and the slot, and electrically connected to the shieldconductor part; and

an internal ground conductor layer disposed in the inside of thedielectric layer between the same surface ground conductor layer and thewaveguide and having a transmission opening for causing anelectromagnetic wave of a signal transmitted through the high frequencyline to be transmitted between the slot and the waveguide.

According to the invention, in a portion of the dielectric layersurrounded by the same surface ground conductor layer disposed on thesame surface so as to surround the line conductor disposed on the onesurface of the dielectric layer and the one end of the line conductor,the shield conductor part disposed on the side of or in the inside ofthe dielectric layer so as to surround the slot, and the waveguideopening part at the side of the other surface of the dielectric layer,and in a portion along the waveguide opening having a highest magneticfield of a TM mode as a resonant mode, since the high frequency linepart and the waveguide opening part are separated by the internal groundconductor layer, an electromagnetic mode transmitted from the highfrequency line to the waveguide is not coupled with the TM mode as theresonant mode, and as a result, a signal energy transmitted through thehigh frequency line is not transferred to the resonant mode, and signalreflection by resonance is made to difficult to generate, so thatexcellent signal conversion from the high frequency line to thewaveguide can be performed.

Besides, in the invention it is preferable a distance between theinternal ground conductor layer and the opening of the waveguide isapproximately (2n−1)/4 (n is a natural number) of a wavelength of anelectromagnetic wave of a signal transmitted through the high frequencyline.

According to the invention, when the distance between the internalground conductor layer and the waveguide is approximately ¼ of thewavelength of the electromagnetic wave excited in the dielectric layerby the signal transmitted through the high frequency line, an opticalpath difference between a reflected wave, which is radiated from theslot, is reflected at the boundary between the dielectric layer and thewaveguide, is again reflected at the internal ground conductor layer,and is again returned to the boundary between the dielectric layer andthe waveguide, and a direct wave directly transmitted from the slot tothe boundary between the dielectric layer and the waveguide becomesapproximately ½ of the wavelength of the electromagnetic wave excited inthe dielectric layer by the signal, and further, the phase of themagnetic field is inverted when the reflected wave is reflected at theboundary between the dielectric layer and the waveguide, andaccordingly, the direct wave and the reflected wave have the same phaseat the boundary between the dielectric layer and the waveguide tointensify each other, and the electromagnetic wave signal is efficientlytransmitted to the waveguide. At this time, when the distance betweenthe internal ground conductor layer and the waveguide is madeapproximately (2n−1)/4 of the wavelength of the electromagnetic waveexcited in the dielectric layer by the signal, where n is a naturalnumber, the optical path difference between the reflected wave and thedirect wave becomes approximately (2n−1)/2 of the wavelength of theelectromagnetic wave, and the same effect as the case where the opticalpath difference between the reflected wave and the direct wave isapproximately ½ of the wavelength of the electromagnetic wave isobtained.

Besides, in the invention it is preferable that an area of thetransmission opening is half or less of an area of a region surroundedby the shield conductor part.

According to the invention, the area of the transmission opening is thehalf or less of the area of the region surrounded by the shieldconductor part, and as a result, the internal ground conductor layeroccupies the half or more of the area surrounded by the shield conductorpart, so that the half or more of the reflected wave radiated from theslot and reflected at the boundary between the dielectric layer and thewaveguide is again reflected at the internal ground conductor layer, thereflected wave and the direct wave from the slot intensify each other,and the conversion efficiency of the high frequency line-to-waveguideconversion can be raised.

Besides, in the invention it is preferable that the shield conductorpart includes a plurality of shield through conductors disposed in theinside of the dielectric layer.

According to the invention, the shield conductor part includes theplurality of shield through conductors disposed in the inside of thedielectric layer, and when the high frequency line-to-waveguideconverter is fabricated, these through conductors can be formed at thesame time as the line conductor, the ground conductor layer, and theinternal ground conductor layer, and the high frequencyline-to-waveguide converter can be easily fabricated.

Besides, in the invention it is preferable that a tip of the one end ofthe line conductor is opened, and a distance between the tip and theslot is approximately (2n−1)/4 (n is a natural number) of the wavelengthof the signal transmitted through the high frequency line.

According to the invention, in the case where the tip of the highfrequency line conductor is opened, and the distance between the opentip and the slot is approximately ¼ of the signal wavelength, an opticalpath length of the high frequency signal transmitted to the open tipfrom the slot, totally reflected at the open tip, and returned to theslot becomes approximately ½ of the signal wavelength, and the phase ofthe magnetic field is inverted by the total reflection at the open tip,and accordingly, the returned high frequency signal comes to have thesame phase as the high frequency signal transmitted through the highfrequency line, and they intensify each other, and are firmly coupledwith the slot, and the conversion efficiency from the high frequencyline to the waveguide can be raised. At this time, when the distancebetween the open tip and the slot is made approximately (2n−1)/4 of thesignal wavelength, where n is a natural number, the optical pathdifference between the reflected wave and the direct wave becomesapproximately (2n−1)/2 of the signal wavelength, and the same effect asthe case where the optical path difference between the reflected waveand the direct wave is approximately ½ of the wavelength of theelectromagnetic wave is obtained.

Besides, in the invention it is preferable that a tip of the one endpart of the line conductor is short-circuited to the same surface groundconductor layer, and the distance between the tip and the slot isapproximately (n−1)/2 (n is a natural number) of the wavelength of thesignal transmitted through the high frequency line.

According to the invention, in the case where the tip of the lineconductor of the high frequency line is short-circuited and the distancebetween the short-circuit tip and the slot becomes approximately ½ ofthe signal wavelength, an optical path length of the high frequencysignal transmitted from the slot to the short-circuit tip, totallyreflected at the short-circuit tip, and returned to the slot comes tohave substantially the same length as the signal wavelength, and sincethe phase of the magnetic field is not changed in the total reflectionat the short-circuit tip, the returned high frequency signal comes tohave the same phase as the high frequency signal transmitted through thehigh frequency line, and they intensify each other and are firmlycoupled with the slot, and the conversion efficiency from the highfrequency line to waveguide can be raised. At this time, when thedistance between the short-circuit tip and the slot is madeapproximately (n−1)/2 of the signal wavelength, where n is a naturalnumber, the high frequency signal transmitted from the slot to theshort-circuit tip, totally reflected at the short-circuit tip, andreturned to the slot comes to have the same phase as the high frequencysignal transmitted through the high frequency line, and they intensifyeach other and are firmly coupled with the slot, and the conversionefficiency from the high frequency line to the waveguide can be raised.Besides, in the case where n is 1, the line conductor is short-circuitedat the slot part, and since the reflection by the short circuit does notchange the phase of the magnetic field, it comes to have the same phaseas the high frequency signal transmitted through the high frequencyline, and they intensify each other.

Besides, in the invention it is preferable that the same surface groundconductor layer and the internal ground conductor layer are connected bya connection conductor disposed to pass through the dielectric layeralong the transmission opening.

According to the invention, the ground conductor layer of the highfrequency line and the internal ground conductor layer are connected bythe connection conductor along the transmission opening, and it becomespossible to effectively use a high frequency line portion outside of theregion surrounded by the connection conductor, and as a result, a systemusing the high frequency line-to-waveguide converter can beminiaturized.

In the invention, it is preferable that a second dielectric layer islaminated on the dielectric layer, and a one surface ground conductorlayer is provided on one surface of the second dielectric layer so as tocover the line conductor, whereby a coplanar line structure havingground is achieved.

The invention provides a high frequency package, wherein a through holeis formed in a metal base having a mounting part of a high frequencyelectronic component on one surface, the through hole being disposed tobe adjacent to the mounting part and having an opening connected with awaveguide on a side of another surface, a connection terminal partincluding a high frequency line conductor directed from an outerperipheral part to a center part on one surface of a dielectricsubstrate and a same surface ground conductor disposed to be close tothe high frequency line conductor is formed on one side of the throughhole, a frame ground conductor having a shape conforming to an openingof the through hole on the one side is formed on another surface of thedielectric substrate so as to be opposite to an end of the highfrequency line conductor on a side of the center part, an internalground conductor provided with a slot coupled with the end of the highfrequency line conductor at the side of the center part in terms of highfrequency is formed between the end of the high frequency line conductorat the side of the center part in the inside of the dielectric substrateand the frame ground conductor, and a conversion substrate in which thesame surface ground conductor is connected to the internal groundconductor through a first connection conductor and the frame groundconductor is connected to the internal ground conductor through a secondconnection conductor, is jointed on the one side of the through holesuch that the connection terminal part is positioned on a side of themounting part and the frame ground conductor is made to conform to theopening of the through hole on the one side.

The invention provides a high frequency package comprising:

a metal base including a mounting part for a high frequency electroniccomponent on one surface thereof, a through hole disposed to be adjacentto the mounting part and having an opening on another side thereofconnected with a waveguide, being formed therein; and

a conversion substrate, including:

a dielectric substrate,

a connection terminal part, including a high frequency line conductordisposed so as to extend from an outer peripheral part toward a centerpart on one surface of the dielectric substrate, and a same surfaceground conductor disposed to be close to the high frequency lineconductor on the one surface of the dielectric substrate,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on one side of the throughhole so as to be opposite to an end of the high frequency line conductoron the center part side,

an internal ground conductor formed in an inside of the dielectricsubstrate and between the end of the high frequency line conductor onthe center part side and the frame ground conductor, the internal groundconductor being provided with a slot coupled to the end of the highfrequency line conductor on the center part side in terms of highfrequency,

a first connection conductor for connecting the same surface groundconductor and the internal ground conductor, and

a second connection conductor for connecting the frame ground conductorand the internal ground conductor,

wherein the conversion substrate is jointed on the one side of thethrough hole of the metal base such that the connection terminal part ispositioned on the side of the mounting part of the metal base and theframe ground conductor is made to conform to the opening on the one sideof the through hole of the metal base.

According to the invention, since the connection terminal part is formedwhich is disposed to be adjacent to the mounting part of the highfrequency electronic component and includes the high frequency lineconductor directed from the outer peripheral part to the center part onthe one surface of the dielectric substrate and the same surface groundconductor disposed to be close to the high frequency line conductor,when the high frequency line conductors of the conversion substrate andthe high frequency electronic component and the same surface groundconductors of these are respectively connected to each other by wirebonding, the connection distance between the high frequency lineconductors can be made substantially equal to the connection distancebetween the same surface ground conductors, and the high frequencypackage can be provided in which the phases of the high frequency signaland the ground potential at the connection part between the conversionsubstrate and the high frequency electronic component are not delayedand the signal transmission is excellent.

Besides, the invention provides a high frequency package, wherein athrough hole is formed in a metal base having a mounting part of a highfrequency electronic component on one surface, the through hole beingdisposed to be adjacent to the mounting part and having an openingconnected with a waveguide on a side of another surface, a connectionterminal part including a high frequency line conductor directed from anouter peripheral part to a center part on one surface of a dielectricsubstrate and a same surface ground conductor disposed on the samesurface so as to surround an end of the high frequency line conductor ona side of the center part is formed on one side of the through hole, aframe ground conductor having a shape conforming to an opening of thethrough hole on the one side is formed on the other surface of thedielectric substrate so as to be opposite to the end of the highfrequency line conductor at the side of the center part, a slot formedto be orthogonal to the end of the high frequency line conductor at theside of the center part and coupled to the high frequency line conductorin terms of high frequency is provided in the same surface groundconductor, and a conversion substrate in which the same surface groundconductor is connected to the frame ground conductor through aconnection conductor is joined on the one side of the through hole suchthat the connection terminal part is positioned on a side of themounting part and the frame ground conductor is made to conform to theopening of the through hole on the one side.

The invention provides a A high frequency package comprising:

a metal base a metal base having a mounting part of a high frequencyelectronic component on one surface, and a through hole disposed to beadjacent to the mounting part, an opening on one side of the throughhole being connected with a waveguide; and

a high frequency line-to-waveguide conversion substrate joined on anopening on another side of the through hole, the high frequencyline-to-waveguide conversion substrate including:

a high frequency line including:

-   -   a dielectric substrate;    -   a high frequency line conductor directed from an outer        peripheral part to a center part on one surface of the        dielectric substrate; and    -   a same surface ground conductor disposed on the same surface as        the one surface of the dielectric substrate so as to surround an        end of the high frequency line conductor on the center part        side,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on another side of thethrough hole so as to be opposite to the end of the high frequency lineconductor on the center part side;

a slot provided on the same surface ground conductor and formed to beorthogonal to the end of the high frequency line conductor on the centerpart side and coupled to the high frequency line in terms of highfrequency; and

a connection conductor for connecting the same surface ground conductorand the frame ground conductors,

wherein the high frequency line-to-waveguide conversion substrate isjoined on the other side of the through hole such that the highfrequency line is positioned on a side of the mounting part and theframe ground conductor is made to conform to the opening on the otherside of the through hole.

The invention provides a high frequency package comprising:

a metal base including a mounting part for a high frequency electriccomponent on one surface thereof, a through hole disposed to be adjacentto the mounting part and having the lower side opening connected withthe waveguide, being formed therein; and

a conversion substrate, including:

a dielectric substrate,

a connection terminal part, including a high frequency line conductorformed on one surface of the dielectric substrate and disposed so as toextend from an outer peripheral part toward a center part on the onesurface of the dielectric substrate, and a same surface ground conductordisposed on the same surface as the one surface of the dielectricsubstrate so as to surround an end of the high frequency line conductoron the center part side, the same surface ground conductor beingprovided with a slot formed to be orthogonal to the end of the highfrequency line conductor on the center part side and coupled with thehigh frequency line conductor in terms of high frequency,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on one side of the throughhole so as to be opposite to the end of the high frequency lineconductor on the center part side, and

a connection conductor for connecting the same surface ground conductorand the frame ground conductors,

wherein the conversion substrate is joined on the one side of thethrough hole of the metal base such that the connection terminal part ispositioned on the side of the mounting part of the metal base and theframe ground conductor is made to conform to the opening on the one sideof the through hole of the metal base.

The invention provides a high frequency package comprising:

a metal base including a mounting part for a high frequency electriccomponent on one surface thereof, a through hole disposed to be adjacentto the mounting part and having an opening on one side connected withthe waveguide, being formed therein; and

a conversion substrate, including:

a high frequency line including:

-   -   a dielectric substrate;    -   a high frequency line conductor formed on one surface of the        dielectric substrate and disposed so as to extend from an outer        peripheral part toward a center part on the one surface of the        dielectric substrate; and    -   a same surface ground conductor disposed on the same surface as        the one surface of the dielectric substrate so as to surround an        end of the high frequency line conductor on the center part        side,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on another side of thethrough hole so as to be opposite to the end of the high frequency lineconductor on the center part side;

a slot provided on the same surface ground conductor and formed to beorthogonal to the end of the high frequency line conductor on the centerpart side and coupled with the high frequency line conductor in terms ofhigh frequency; and

a connection conductor for connecting the same surface ground conductorand the frame ground conductors,

wherein the conversion substrate is joined on the other side of thethrough hole of the metal base such that the high frequency line ispositioned on the side of the mounting part of the metal base and theframe ground conductor is made to conform to the opening on the otherside of the through hole of the metal base.

According to the invention, since the connection terminal part is formedwhich is disposed to be adjacent to the mounting part of the highfrequency electronic component and includes the high frequency lineconductor directed from the outer peripheral part to the center part onthe one surface of the dielectric substrate and the same surface groundconductor disposed on the same surface so as to surround the end of thehigh frequency line conductor at the side of the center part, when thehigh frequency line conductors of the conversion substrate and the highfrequency electronic component and the same surface ground conductors ofthese are respectively connected to each other by wire bonding, theconnection distance between the high frequency line conductors can bemade substantially equal to the connection distance between the samesurface ground conductors, and the high frequency package can beprovided in which the phases of the high frequency signal and the groundpotential at the connection part between the conversion substrate andthe high frequency electronic component are not delayed and the signaltransmission is excellent.

Besides, the invention provides a high frequency package, wherein athrough hole is formed in a metal base having a mounting part of a highfrequency electronic component on one surface, the through hole beingdisposed to be adjacent to the mounting part and having an openingconnected with a waveguide on a side of the other surface, a connectionterminal part including a high frequency line conductor directed from anouter peripheral part to a center part on one surface of a dielectricsubstrate and a same surface ground conductor disposed on the samesurface so as to surround an end of the high frequency line conductor ona side of the center part is formed on one side of the through hole, aframe ground conductor having a shape conforming to an opening of thethrough hole on the one side is formed on the other surface of thedielectric substrate so as to be opposite to the end of the highfrequency line conductor at the side of the center part, a slot formedto be orthogonal to the end of the high frequency line conductor at theside of the center part and coupled with the high frequency lineconductor in terms of high frequency is formed in the same surfaceground conductor, an internal ground conductor provided with atransmission opening opposite to the slot and larger than the slot isformed between the high frequency line conductor in an inside of thedielectric substrate and the frame ground conductor, and a conversionsubstrate in which the same surface ground conductor is connected to theinternal ground conductor through a first connection conductor and theframe ground conductor is connected to the internal ground conductorthrough a second connection conductor, is jointed on the one side of thethrough hole such that the connection terminal part is positioned on aside of the mounting part and the frame ground conductor is made toconform to the opening of the through hole on the one side.

The invention provides a high frequency package comprising:

a metal base a metal base having a mounting part of a high frequencyelectronic component on one surface, and a through hole disposed to beadjacent to the mounting part, an opening on one side of the throughhole being connected with a waveguide; and

a high frequency line-to-waveguide conversion substrate joined on anopening on another side of the through hole, the high frequencyline-to-waveguide conversion substrate including:

a high frequency line including:

-   -   a dielectric substrate;    -   a high frequency line conductor directed from an outer        peripheral part to a center part on one surface of a dielectric        substrate; and    -   a same surface ground conductor disposed on the same surface as        the one surface of the dielectric substrate so as to surround an        end of the high frequency line conductor on the center part        side,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on another side of thethrough hole so as to be opposite to the end of the high frequency lineconductor on the center part side;

a slot provided on the same surface ground conductor and formed to beorthogonal to the end of the high frequency line conductor on the centerpart side and coupled to the high frequency line in terms of highfrequency;

a internal ground conductor formed between the high frequency lineconductor of an inside of the dielectric substrate and the frame groundconductor, and provided with the transmission opening opposite to theslot and larger than the slot;

a first connection conductor for connecting the same surface groundconductor and internal ground conductor; and

a second connection conductor for connecting the frame ground conductorand the internal ground conductor,

wherein the high frequency line-to-waveguide conversion substrate isjointed on the other side of the through hole such that the highfrequency line is positioned on a side of the mounting part and theframe ground conductor is made to conform to the opening on the otherside of the through hole.

The invention provides a high frequency package comprising:

a metal base including a mounting part for high a frequency electriccomponent at one surface thereof, the through hole disposed to beadjacent to the mounting part and having an opening on another sidethereof connected with the waveguide, being formed therein; and

a conversion substrate including:

a dielectric substrate

a connection terminal part including a high frequency line conductordisposed so as to extend from an outer peripheral part toward a centerpart on one surface of the dielectric substrate, and a same surfaceground conductor disposed on the same surface as the one surface of thedielectric substrate so as to surround an end of the high frequency lineconductor on the center part side, the same surface ground conductorbeing provided with a slot formed to be orthogonal to the end of thehigh frequency line conductor on the center part side and coupled withthe high frequency line conductor in terms of high frequency,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on one side of the throughhole so as to be opposite to the end of the high frequency lineconductor on the center part side,

a internal ground conductor formed between the high frequency lineconductor of an inside of the dielectric substrate and the frame groundconductor, and provided with the transmission opening opposite to theslot and larger than the slot,

a first connection conductor for connecting the same surface groundconductor and internal ground conductor, and

a second connection conductor for connecting the frame ground conductorand the internal ground conductor,

wherein the conversion substrate is joined on the one side of thethrough hole of the metal base such that the connection terminal part ispositioned on the side of the mounting part of the metal base and theframe ground conductor is made to conform to the opening on the one sideof the through hole of the metal base.

The invention provides a high frequency package comprising:

a metal base including a mounting part for high a frequency electriccomponent at one surface thereof, the through hole disposed to beadjacent to the mounting part and having an opening on one side thereofconnected with the waveguide, being formed therein; and

a conversion substrate including:

a high frequency line including:

-   -   a dielectric substrate;    -   a high frequency line conductor disposed so as to extend from an        outer peripheral part toward a center part on one surface of the        dielectric substrate; and    -   a same surface ground conductor disposed on the same surface as        the one surface of the dielectric substrate so as to surround an        end of the high frequency line conductor on the center part        side,

a frame ground conductor formed on another surface of the dielectricsubstrate in a shape conforming to an opening on another side of thethrough hole so as to be opposite to the end of the high frequency lineconductor on the center part side;

a slot provided on the same surface ground conductor and formed to beorthogonal to the end of the high frequency line conductor on the centerpart side and coupled with the high frequency line conductor in terms ofhigh frequency;

a internal ground conductor formed between the high frequency lineconductor of an inside of the dielectric substrate and the frame groundconductor, and provided with the transmission opening opposite to theslot and larger than the slot;

a first connection conductor for connecting the same surface groundconductor and internal ground conductor; and

a second connection conductor for connecting the frame ground conductorand the internal ground conductor,

wherein the conversion substrate is joined on the other side of thethrough hole of the metal base such that the high frequency line ispositioned on the side of the mounting part of the metal base and theframe ground conductor is made to conform to the opening on the otherside of the through hole of the metal base.

According to the invention, since the connection terminal part is formedwhich is disposed to be adjacent to the mounting part of the highfrequency electronic component and includes the high frequency lineconductor directed from the outer peripheral part to the center part onthe one surface of the dielectric substrate and the same surface groundconductor disposed on the same surface so as to surround the end of thehigh frequency line conductor at the side of the center part, when thehigh frequency line conductors of the conversion substrate and the highfrequency electronic component and the same surface ground conductors ofthese are respectively connected to each other by wire bonding, theconnection distance between the high frequency line conductors can bemade substantially equal to the connection distance between the samesurface ground conductors, and the high frequency package can beprovided in which the phases of the high frequency signal and the groundpotential at the connection part between the conversion substrate andthe high frequency electronic component are not delayed and the signaltransmission is excellent.

Besides, in the invention it is preferable that an interval between thehigh frequency line conductor and the same surface ground conductor is ¼or less of a signal wavelength of a high frequency signal transmittedthrough the high frequency line.

According to the invention, in the above structure, when the intervalbetween the high frequency line conductor and the same surface groundconductor is ¼ or less of the signal wavelength of the high frequencysignal transmitted through the high frequency line, in the case wherethe high frequency line conductors of the conversion substrate and thehigh frequency electronic component and the same surface groundconductors of these are respectively connected to each other by wirebonding, the distance between the wire for connecting the high frequencyline conductors and the wire for connecting the same surface groundconductors can be made approximately ¼ or less of the signal wavelengthof the high frequency signal, and the respective wires areelectromagnetically coupled with each other to form the high frequencytransmission path, and the high frequency package excellent intransmission of high frequency signals can be provided.

Besides, according to the invention, since the high frequency electroniccomponent mounting part and the conversion substrate can be separated,the conversion substrate can be miniaturized, the stress due todifference in thermal expansion coefficient between the substrate andthe metal base can be reduced, and the warp or crack of the package canbe prevented.

Besides, according to the invention, the dielectric waveguide partsurrounded by the internal ground conductor and the second connectionconductor is shielded by the internal ground conductor from the highfrequency electromagnetic field generated in the high frequency lineconductor part of the one surface. For example, although the magneticfield circulating through the high frequency line conductor is generatedin the high frequency line conductor part, part of the magnetic field iscoincident with the magnetic field of the TM mode as one of resonantmodes in the dielectric waveguide part, and these two magnetic fieldsare shielded by the internal ground conductor, so that a possibility tocause an unnecessary resonance in the dielectric waveguide part isreduced, and excellent conversion to the waveguide can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, features, and advantages of the inventionwill be more explicit from the following detailed description taken withreference to the drawings wherein:

FIG. 1A is a plan view showing a high frequency line-to-waveguideconverter according to one embodiment of the invention, FIG. 1B is asectional view taken along line I-I of FIG. 1A, and FIG. 1C is asectional view showing a variation of a high frequency line-to-waveguideconverter according to one embodiment of the invention.

FIG. 2A is a plan view showing a high frequency line-to-waveguideconverter according to another embodiment of the invention, FIG. 2B is asectional view taken along line II-II of FIG. 2A, and FIG. 2C is asectional view showing a variation of a high frequency line-to-waveguideconverter according to another embodiment of the invention.

FIG. 3A is a plan view showing a high frequency line-to-waveguideconverter according to still another embodiment of the invention, andFIG. 3B is a sectional view taken along line III-III of FIG. 3A.

FIG. 4A is a plan view showing a high frequency line-to-waveguideconverter according to still another embodiment of the invention, andFIG. 4B is a sectional view taken along line IV-IV of FIG. 4A.

FIGS. 5A to 5C show an evaluation substrate of a high frequencyline-to-waveguide converter of the invention, in which FIG. 5A is a topview, FIG. 5B is a sectional view taken along line V-V of FIG. 5A, andFIG. 5C is a bottom view.

FIG. 6A is a plan view showing a high frequency line-to-waveguideconverter according to still another embodiment of the invention, FIG.6B is a sectional view taken along line VI-VI of FIG. 6A, and FIG. 6C isa sectional view showing a variation of a high frequencyline-to-waveguide converter according to still another embodiment of theinvention.

FIG. 7A is a perspective view of a case where a TE mode occurs in adielectric layer in the example shown in FIGS. 6A and 6B, and FIG. 7B isa perspective view of a case where a TM mode occurs in the dielectriclayer.

FIGS. 8A to 8C are plan views showing a line conductor according tostill another embodiment of the invention, in which FIG. 8A shows anexample in which a tip of the line conductor is opened, FIG. 8B shows anexample in which the tip of the line conductor is short-circuited, andFIG. 8C shows an example in which n is made 1 in FIG. 8B.

FIGS. 9A to 9C show an evaluation substrate of a high frequencyline-to-waveguide converter of the invention, in which FIG. 9A is a topview, FIG. 9B is a sectional view taken along line VII-VII of FIG. 9A,and FIG. 9C is a bottom view.

FIGS. 10A and 10B are views showing a high frequency package accordingto still another embodiment of the invention, in which FIG. 10A is aplan view, and FIG. 10B is a sectional view taken along line VIII-VIIIof FIG. 10A.

FIGS. 11A and 11B are views showing a high frequency package accordingto still another embodiment of the invention, in which FIG. 11A is aplan view, and FIG. 11B is a sectional view taken along line IX-IX ofFIG. 11A.

FIGS. 12A and 12B are views showing a high frequency package accordingto still another embodiment of the invention, in which. FIG. 12A is aplan view, and FIG. 12B is a sectional view taken along line X-X of FIG.12A.

FIG. 13 is a plan view showing a high frequency line conductor of aconversion substrate of the high frequency package according to stillanother embodiment of the invention.

FIG. 14 is a sectional view showing an example of a conventional highfrequency line-to-waveguide converter.

FIG. 15 is a sectional view showing another example of a conventionalhigh frequency line-to-waveguide converter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now referring to the drawings, preferred embodiments of the inventionare described below.

FIGS. 1A and 1B are views showing a high frequency line-to-waveguideconverter according to still another embodiment of the invention, inwhich FIG. 1A is a plan view, and FIG. 1B is a sectional view takenalong line I-I. Besides, FIGS. 2A and 2B are views showing a highfrequency line-to-waveguide converter according to another embodiment ofthe invention, in which FIG. 2A is a plan view and FIG. 2B is asectional view taken along line II-II. In FIGS. 1A and 1B and FIGS. 2Aand 2B, reference numeral 41 denotes a high frequency line; referencenumeral 42 denotes a dielectric layer; reference numeral 43 denotes aline conductor; reference numeral denotes 44 a ground conductor layer;reference numeral 45 denotes a slot formed in the ground conductor layer44; reference numeral 46 denotes a waveguide; and reference numerals 47a, 47 b and 47 c denote shield conductor parts.

In the examples of the high frequency line-to-waveguide converter of theinvention, a coplanar line as the high frequency line 41 is formed ofthe dielectric layer 42, the line conductor 43 disposed on the uppersurface, as one surface, of the dielectric layer 42, and the groundconductor layer 44 disposed on the same surface (upper surface of thedielectric layer 42) so as to surround one end of the line conductor 43.Besides, the slot 45 formed to be substantially orthogonal to the oneend of the line conductor 43 is disposed in the ground conductor layer44 on the upper surface of the dielectric layer 42, and iselectromagnetically coupled to the one end of the high frequency line41. By this, a high frequency signal transmitted to the high frequencyline 41 is radiated as an electromagnetic wave from the slot 45 into thewaveguide 46 whose opening is positioned at the side of the lowersurface, as another surface, of the dielectric layer 42 so as to beopposite to the one end of the line conductor 43 and the slot 45, andwhich is disposed to extend downward.

The side direction of the dielectric layer 42 is shielded by the shieldconductor parts 47 a, 47 b and 47 c disposed at the side of thedielectric layer 42 as shown in the example of FIGS. 1A and 1B or in theinside of the dielectric layer 42 as shown in the example of FIGS. 2Aand 2B so as to surround the one end of the line conductor 43 and theslot 45, and the electromagnetic wave radiated from the slot 45 to thedielectric layer 42 and the electromagnetic wave reflected at theboundary between the dielectric layer 42 and the waveguide 46 areprevented from leaking out, and the conversion efficiency is preventedfrom lowering.

Since the line conductor 43 and the ground conductor layer 44constituting the coplanar line as the high frequency line 41 and theslot 45 can be formed on the same surface by adopting the structure asstated above, as compared with the case where the line conductor 43 andthe ground conductor layer 44, and the slot 45 are formed in differentlayers, a shift of relative position of both due to a lamination shiftdoes not occur, and control of an electromagnetic couplingcharacteristic of the high frequency line 41 and the slot 45 becomeseasy, and as a result, it becomes possible to perform a control so as toraise the conversion efficiency of the high frequency line-to-waveguideconversion, and a variation in conversion characteristic can besuppressed to be small.

Besides, since the high frequency line 41 is constituted by the lineconductor 43 disposed on the upper surface of the dielectric layer 42and the ground conductor layer 44, and the line conductor 43 and theground conductor layer 44 constituting the high frequency line 41 andthe slot 45 are disposed on the same surface of the upper surface of thedielectric layer 42, it is easy to check the relative position betweenthe high frequency line 41 and the slot 45 from the outside after theseare fabricated, and it is easy to feed back the relative position to afabrication process so that the electromagnetic coupling characteristicbetween the high frequency line 41 and the slot 45 becomes excellent, orto improve fabrication yield through selection of poor products by checkand to suppress the outflow of the poor products.

As a dielectric material forming the dielectric layer 42, aluminumoxide, aluminum nitride, silicon nitride, ceramic material containingmullite or the like as its main ingredient, glass, glass ceramicmaterial formed by firing a mixture of glass and ceramic filler, epoxyresin, polyimide resin, organic resin material such as fluorine resinincluding tetrafluoroethylene resin, organic resin-ceramic (includingglass) composite material or the like is used.

As a conductor material forming the line conductor 43, the groundconductor layer 44, the shield conductor part 47 c of the throughconductor or the like, a metalized material containing tungsten,molybdenum, gold, silver, copper or the like as its main ingredient, ora metal foil containing gold, silver, copper, aluminum or the like asits main ingredient is used.

Especially in the case where the high frequency line-to-waveguideconverter is incorporated in a wiring substrate on which a highfrequency component is mounted, as a dielectric material forming thedielectric layer 42, it is desirable that a dielectric loss tangent issmall, and airtight sealing is possible. As an especially desirabledielectric material, at least one kind of inorganic material selectedfrom a group consisting of aluminum oxide, aluminum nitride, and glassceramic material can be mentioned. When such a hard material is used,the dielectric loss tangent is small and the mounted high frequencycomponent can be airtightly sealed, so that such a material ispreferable in raising the reliability of the mounted high frequencycomponent. In this case, as a conductor material, it is desirable inview of airtightness and productivity to use a metalized conductor whichcan be fired at the same time as the dielectric material.

The high frequency line-to-waveguide converter of the invention isfabricated as described below. For example, in the case where analuminum oxide sintered body is used as the dielectric material, first,a suitable organic solvent is added to and mixed with a raw materialpowder of aluminum oxide, silicon oxide, magnesium oxide, calcium oxideor the like to form slurry, and this is formed into a sheet by awell-known doctor blade method or a calendar roll method to fabricate aceramic green sheet. Besides, a suitable organic solvent is added to andmixed with a raw material powder of high melting metal, such as tungstenor molybdenum, aluminum oxide, silicon oxide, magnesium oxide, calciumoxide or the like to fabricate a metallization paste. Next, throughholes for formation of through conductors as the shield conductor part47 c are formed in the ceramic green sheet by, for example, a punchingmethod, and the metallization paste is implanted in the through holesby, for example, a printing method, and subsequently, the metallizationpaste is printed to have the shape of the ground conductor 44 having theline conductor 43 and the slot 45. In the case where the dielectriclayer 42 is made of a laminate structure having a plurality ofdielectric layers, ceramic green sheets in which these conductors areimplanted and printed are laminated, are pressurized to be subjected topressure bonding, and are fired at a high temperature (about 1600° C.).Further, the surface of the conductor exposed on the surface of the lineconductor 43, the ground conductor 44 or the like is plated with nickeland gold.

The shield conductor parts 47 a, 47 b and 47 c are disposed on the sideof or in the inside of the dielectric layer 42 so as to surround the oneend of the line conductor 43 and the slot 45, and are electricallyconnected to the ground conductor layer 44 to be grounded.

FIGS. 1A and 1B shows the example in which the shield conductor parts 47a and 47 b are disposed on the side of the dielectric layer 42, and atube wall of an end of the waveguide 46 serves also as the shieldconductor part 47 b. The shield conductor parts 47 a and 47 b in thiscase may be metallized layers formed on the side of the dielectric layer42, and the metallized layers on the side at that time have only to beformed so as to be electrically connected to the waveguide 46. Withrespect to the connection of the waveguide 46 to the metallized layerson the side in this case, although the connection may be performed suchthat the opening of the waveguide 46 is positioned at the lower surfaceof the dielectric layer 42, in order to suppress the leakage of anelectromagnetic wave, as shown in FIGS. 1A and 1B, it is desirable thatthe waveguide 46 is set so that the lower surface of the dielectriclayer 42 is positioned inside of the opening of the waveguide 46.Besides, the formation of the metalized layers onto the side of thedielectric layer 42 may be performed by a method in which in theforegoing fabrication method, after the ceramic green sheet is subjectedto pressure bonding, the metallization paste is applied by printing to aportion of the side of the laminate body which becomes the dielectriclayer 42, or a method in which after the side of the dielectric layer 42is polished as the need arises after firing, the metallization paste isapplied to the side by printing and is fired.

As shown in FIGS. 2A and 2B, it is appropriate that the shield conductorpart 47 c is constituted by a plurality of shield through conductorsdisposed in the inside of the dielectric layer 42. In the example shownin FIGS. 2A and 2B, the plurality of shield through conductors arearranged in the dielectric layer 42 so as to surround the one end of theline conductor 43 and the slot 45 and form the shield conductor part 47c. At this time, it is desirable that the shield through conductors areset to be positioned inside of the opening of the waveguide 46 so thatunnecessary resonance does not occur. As stated above, when the shieldconductor part 47 c is formed of the plurality of shield throughconductors, at the time of fabrication thereof, they can be formed inthe dielectric layer 42 at the same time as the line conductor 43 on theupper surface and the ground conductor layer 44. Accordingly, it becomespossible to omit a step of separately forming the shield conductor part47 c on the side of the dielectric layer 42, and contrary to the case ofthe example shown in FIGS. 1A and 1B, it is not necessary to adjust theouter shape of the dielectric layer 42 so as to put the dielectric layerin the opening of the waveguide 46, and the high frequencyline-to-waveguide converter can be easily fabricated. Besides, since theshape of the region of the dielectric layer 42 surrounded by the shieldconductor part 47 c can be arbitrarily designed, for example, in thecase where unnecessary resonance occurs in the region of the dielectriclayer 42 surrounded by the shield conductor part 47 c, the arrangementof the shield conductor part 47 c is adjusted, and it becomes possibleto shift the unnecessary resonance to the outside of the band of signalconversion.

It is desirable that a gap (indicated by G in FIG. 2A) between theshield through conductors is made less than ¼ of the signal wavelength.This is because when the gap is made less than ¼ of the signalwavelength, the electromagnetic wave becomes difficult to leak from thegap between the shield through conductors, and the shield effect can beenhanced.

Incidentally, the shield through conductor constituting the shieldconductor part 47 c may be a so-called through hole conductor in whichan inner wall of the through hole is coated with a conductor layer, ormay be a so-called via conductor in which the inside of the through holeis filled with a conductor.

In order to enhance the conversion efficiency of the high frequencyline-to-waveguide converter, it is preferable that the thickness(indicated by H in FIG. 1B) of the dielectric layer 42 is madeapproximately ¼ of the wavelength of a signal transmitted through thehigh frequency line 41. When the thickness of the dielectric layer 42 ismade approximately ¼ of the wavelength of the signal, the distance fromthe slot 45 to the boundary between the dielectric layer 42 and thewaveguide 46 becomes approximately ¼ of the signal wavelength, and theoptical path length in which the reflected wave reflected at theboundary between the dielectric layer 42 and the waveguide 46 is totallyreflected at the ground conductor layer 44 and is returned to theboundary becomes approximately ½ of the signal wavelength. Accordingly,when the reflected wave is returned, the phase is inverted, and incombination with the phase inversion by the total reflection at theground conductor layer 44, the reflected wave comes to have the samephase as the direct wave directly transmitted to the boundary from theslot 45, and these are combined with each other, and the signal isefficiently transmitted to the waveguide 46. Incidentally, when thethickness of the dielectric layer 42 is made (2n−1)/4 of the signalwavelength, where n is a natural number, the optical path differencebetween the reflected wave and the direct wave becomes substantially ½of the signal wavelength, and the same effect as the above can beobtained. Together with that, the signal frequency becomes high, and thesignal wavelength becomes short, and when the thickness of thedielectric layer 42 is set to ¼ of the signal wavelength, in the casewhere the strength of the dielectric layer 42 is lowered, it is possibleto suppress the lowering of the strength of the dielectric layer 42 bysetting the thickness of the dielectric layer 42 to ¾, 5/4 or the likeof the signal wavelength.

The thickness of the dielectric layer 42 can be adjusted in theforegoing fabrication method by adjusting the thickness of the ceramicgreen sheet which becomes the dielectric layer 42 after firing. In thiscase, the adjustment may be made by the thickness of one ceramic greensheet, or the adjustment may be made by laminating a plurality ofceramic green sheets.

Next, FIGS. 3A and 3B are views showing a high frequencyline-to-waveguide converter according to still another embodiment of theinvention, in which FIG. 3A is a plan view, and FIG. 3B is a sectionalview taken along line III-III. In FIGS. 3A and 3B, reference numeral 51denotes a coplanar line as a high frequency line; reference numeral 52denotes a dielectric layer; reference numeral 53 denotes a lineconductor; reference numeral 54 denotes a ground conductor layer;reference numeral 55 denotes a slot formed in the ground conductor layer54; reference numeral 46 denotes a waveguide; and reference numeral 47 cdenotes a shield conductor part. In this embodiment, the coplanar lineas the high frequency line 51 includes the dielectric layer 52, the lineconductor 53 disposed on a surface of the dielectric layer 52 and theground conductor layer 54 disposed on the same place surrounding one endof the line conductor 53.

In the example of the high frequency line-to-waveguide converter of thisinvention, a tip of the line conductor 53 of the coplanar line as thehigh frequency line 51 is opened, namely, apart from the groundconductor layer 54, and a distance from the opened tip of the lineconductor 53 to the center of the slot 55 is set to (2n−1)/4 of thesignal wavelength, where n is a natural number. By this, in a standingwave formed by synthesis of a traveling wave transmitted through thecoplanar line and a regressive wave reflected at the opened tip, amagnetic field becomes highest at a portion of the slot 45, so thatelectromagnetic coupling from the coplanar line to the slot 45 throughthe magnetic field is most excellently performed, and the conversionefficiency of the high frequency line-to-waveguide conversion can beenhanced.

Next, FIGS. 4A and 4B are views showing a high frequencyline-to-waveguide converter according to still another embodiment of theinvention, in which FIG. 4A is a plan view, and FIG. 4B is a sectionalview taken along line IV-IV. In FIGS. 4A and 4B, reference numeral 61denotes a coplanar line as a high frequency line; reference numeral 52denotes a dielectric layer; reference numeral 63 denotes a lineconductor; reference numeral 54 denotes a ground conductor layer;reference numeral 45 denotes a slot formed in the ground conductor layer54; reference numeral 46 denotes a waveguide; and reference numeral 47 cdenotes a shield conductor part. In this embodiment, a coplanar line asthe high frequency line 61 includes the dielectric layer 52, the lineconductor 63 disposed at the upper surface of the dielectric layer 52and the ground conductor layer 54 disposed on the same surfacesurrounding one end of the line conductor 63.

In the example of the high frequency line-to-waveguide converter of theinvention, a tip of the line conductor 63 of the coplanar line as thehigh frequency line 61 is short-circuited to the ground conductor layer54, and a distance from the short-circuited tip to the center of theslot 45 is set to (n−1)/2 of a signal wavelength, where n is a naturalnumber. By this, in a standing wave formed by synthesis of a travelingwave transmitted through the coplanar line and a regressive wavereflected at the short-circuited tip, a magnetic field becomes highestat a portion of the slot 45, and electromagnetic coupling from thecoplanar line to the slot 45 through the magnetic field is performedmost excellently, and the conversion efficiency of the high frequencyline-to-waveguide conversion can be enhanced. Incidentally, the examplesshown in FIGS. 1A and 1B and FIGS. 2A and 2B correspond to the casewhere n is made 1 in this example.

The shape of the waveguide 46 is not particularly restricted, and forexample, when a WR series normalized as a rectangular waveguide is used,since a measuring correction kit is substantial, various characteristicevaluations become easy. However, for miniaturization and reduction inweight of a system according to the frequency of a high frequency signalto be used, a miniaturized rectangular waveguide may be used within therange where cutoff of the waveguide does not occur. Besides, a circularwaveguide may be used.

The waveguide 46 is formed of metal, and it is appropriate that the wallin the tube is coated with novel metal, such as gold or silver, in orderto reduce a conductor loss due to current or to prevent corrosion.Besides, resin is molded into a necessary waveguide shape, and similarlyto the case of metal, the wall in the tube may be coated with novelmetal such as gold or silver. The attachment of the waveguide 46 to thehigh frequency line-to-waveguide converter is performed by joining withsolder material, screwing or the like.

In order to attach the waveguide 46 to the high frequencyline-to-waveguide converter by joining with solder material, it isappropriate that a waveguide connecting conductor electrically connectedto the ground conductor layer 54 and the shield conductor part 47 c ispreviously formed to conform to the opening of the waveguide 46 to beattached. For example, as shown in FIGS. 2A and 2B, it is appropriatethat a waveguide connecting conductor 48 made of a metallized layerconnected to the shield conductor part 47 c made of the shield throughconductor is previously formed on the lower surface of the dielectriclayer 42. Besides, also in the case where the shield conductor part is ametallized layer formed on the side of the dielectric layer 42, it isappropriate that the waveguide connecting conductor 48 made of ametallized layer is formed on the lower surface of the dielectric layer42 so as to be connected to the metallized layer as the shield conductorpart on the side. When the waveguide connecting conductor 48 as statedabove is previously formed, the electrical connection between thewaveguide 46 and the shield conductor and the ground conductor layer 44at the time when the waveguide 46 is attached to the high frequencyline-to-waveguide converter becomes more certain, and accordingly, thisbecomes preferable in that the high frequency line-to-waveguideconverter having high reliability can be constructed.

The waveguide connection conductor 48 may be simultaneously formed, inthe foregoing fabrication method, by printing metallization paste intothe shape of the waveguide connection conductor 48 similarly to theformation of the line conductor 43,53,63, the ground conductor layer44,54. Further, similarly to the conductor exposed on the surface, suchas the line conductor 43,53,63 and the ground conductor layer 44,54,when the surface is plated with nickel and gold, the wettability of thesolder material in the case of the joining with the solder material isimproved, and according, this is more desirable.

For example, although FIGS. 1A and 1B and FIGS. 2A and 2B show theexamples in which the high frequency line has the coplanar linestructure, a coplanar line structure having a ground may be adopted inwhich a lower ground layer is provided between the line conductor43,53,63 and the waveguide 46, or a coplanar line structure havingground may be adopted in which a dielectric layer 42 a is furtherlaminated on the dielectric layer 42, and an upper ground conductorlayer 44 a is provided on the upper surface of the dielectric layer 42 aso as to cover the line conductor 43, as shown in FIGS. 1C and 2C. Inany case, when the positional relation among the dielectric layer 42,52,the line conductor 43,53,63, the ground conductor layer 44,54, the slot45, the waveguide 46 and the shield part 47 a,47 b,47 c is made the sameas the example shown in FIGS. 1A and 1B or FIGS. 2A and 2B, the sameeffect can be obtained.

Besides, in the foregoing example of the embodiment, although thedescription has been given of the fabrication method of the case wherethe aluminum oxide sintered body is used as the dielectric material, inthe case where a glass ceramic sintered body is used as the dielectricmaterial, in the foregoing fabrication method, as a raw material powderof a ceramic green sheet, a powder of a glass ceramic component is used,and as a raw material powder of metallization paste, in addition to theuse of low melting metal such as silver, copper or gold, when a greensheet of an inorganic component which is not substantially sintered andshrunk at a temperature at which the glass ceramic material is sintered,for example, alumina is laminated on both surfaces of a laminate and isfired, firing shrinkage in an X-Y plane direction can be suppressed, sothat it becomes possible to suppress variation in size of a ceramicwiring substrate due to variation in firing shrinkage, and the highfrequency line-to-waveguide converter which further suppresses variationin size of a slot and in length of a stub can be obtained, which isadvantageous.

EXAMPLE

Next, in order to confirm the effect of the high frequencyline-to-waveguide converter of the invention, an experiment as describedbelow was carried out.

First, by using a ceramic green sheet of alumina ceramic whosedielectric loss tangent at 10 GHz became 0.0006 after firing and ametallization paste for tungsten metallization, an evaluation substrateas shown in FIGS. 5A to 5C was fabricated by a normal green sheetlamination technique and a simultaneous firing technique. Incidentally,

FIG. 5A is a top view of the evaluation substrate, FIG. 5B is asectional view taken along line V-V of FIG. 5A, and FIG. 5C is a bottomview.

After firing, the surfaces of respective metallized layers of the uppersurface and the lower surface of the evaluation substrate were subjectedto plating with nickel and gold. Here, with respect to the highfrequency line-to-waveguide converter in the evaluation substrate, thecorresponding waveguide was set to a WR-10 for a W band (75 GHz to 110GHz), and was designed while 76 GHz was made the center frequency. Theevaluation substrate includes two high frequency line-to-waveguideconverters of the invention at both sides in the drawing, each includingthe dielectric layer 42, the line conductor 43, the ground conductorlayer 44, the slot 45, the shield conductor part 47 c made of the shieldthrough conductors, and the waveguide connection conductor 48 as shownin FIGS. 2A and 2B, and these two converters have such a structure thatthe line conductors 43, the ground conductor layers 44 of both arerespectively integrated. The integrated line conductor 43 and groundconductor layer 44, together with the dielectric layer 42, constitutethe connection coplanar line 49. The interval between the high frequencyline-to-waveguide converters at both sides was made 20 mm so thatmeasuring waveguides could be respectively connected. By this, theevaluation substrate has such a structure that the two high frequencyline-to-waveguide converters are connected by the connection coplanarline 49 having a length of 20 mm.

Next, an insertion loss within the range of 75 GHz to 110 GHz wasmeasured by a method in which a waveguide opening of a measuringwaveguide was made to conform to the waveguide connecting conductor 48of each of the high frequency line-to-waveguide converters of thisevaluation substrate and was connected by screwing, a signal wasinputted from one of the waveguides, and the signal outputted from theother of the waveguides was measured. From the result and the separatelymeasured loss of the connecting coplanar line 49, the conversion loss ofthe high frequency line-to-waveguide converter was estimated.

As a result, the conversion loss at 76 GHz was about 0.7 dB, and it wasconfirmed that the conversion loss was sufficiently small in fabricationof a practical high frequency module.

Now referring to the drawings, preferred embodiments of the inventionare described below.

FIGS. 6A and 6B are views showing a high frequency line-to-waveguideconverter according to still another embodiment of the invention, inwhich FIG. 6A is a plan view, and FIG. 6B is a sectional view takenalong line VI-VI.

FIGS. 7A and 7B are views showing modes in the respective parts in theexample shown in FIG. 6A, in which FIG. 7A shows a case where a TE modeoccurs in a dielectric layer and conversion is excellently performed,and FIG. 7B shows a case where a TM mode occurs in the dielectric layerand a signal is reflected. In FIGS. 6A and 6B and FIGS. 7A and 7B,reference numeral 71 denotes a coplanar line as a high frequency line;reference numeral 72 denotes a dielectric layer; reference numeral 73denotes a line conductor; reference numeral 74 denotes a groundconductor layer; reference numeral 75 denotes a slot formed in theground conductor layer 74; reference numeral 76 denotes a waveguide;reference numeral 77 denotes a shield conductor part; reference numeral78 denotes an internal ground conductor layer; reference numeral 79denotes a transmission opening formed in the internal ground conductorlayer; and reference numeral 80 denotes a connection conductor forconnecting the ground conductor layer 74 and the internal groundconductor layer 78.

In the example of the high frequency line-to-waveguide converter of theinvention, the coplanar line as the high frequency line 71 is formed ofthe dielectric layer 72, the line conductor 73 disposed on the uppersurface of the dielectric layer 72, and the ground conductor layer 74.Besides, the slot 75 is disposed in the ground conductor layer 74 on theupper surface of the dielectric layer 72, and is coupled with one end ofthe high frequency line 71 in terms of high frequency. By this, a highfrequency signal transmitted to the high frequency line 71 is radiatedas an electromagnetic wave from the slot 75 into the waveguide 76disposed so as to extend downward. The side direction of the dielectriclayer 72 is shielded by a conductor formed on the side or the shieldconductor part 77 disposed in the inside as shown in FIGS. 6A and 6B,and this prevents the electromagnetic wave radiated from the slot 75 tothe dielectric layer 72 and the electromagnetic wave reflected at theboundary between the dielectric layer 72 and the waveguide 76 fromleaking out, and prevents the conversion efficiency from lowering.Besides, the internal ground conductor layer 78 is disposed between theground conductor layer 74 and the waveguide 76, and the ground conductorlayer 74 and the internal ground conductor layer 78 are connected by theconnection conductor 80.

By adopting the structure as stated above, as shown in FIG. 7B, portionswhere a magnetic field distribution 83 of the coplanar line as the highfrequency line 71 and a magnetic field distribution 85 of an unnecessarymode in the dielectric layer exist, are separated by the internal groundconductor layer 78 from the side of the dielectric layer 72 where thewaveguide 76 is attached, and the occurrence of the unnecessary mode inthe portion of the internal ground conductor layer 78 at the side of thewaveguide 76 is suppressed, and as a result, it is possible to suppressthe occurrence of reflection due to the resonance of the unnecessarymode in the high frequency line-to-waveguide conversion.

Besides, when the distance between the internal ground conductor layer78 and the waveguide 76 is made approximately (2n−1)/4 (n is a naturalnumber) of the wavelength of the electromagnetic wave excited in thedielectric layer 72 by the signal transmitted through the high frequencyline 71, an optical path difference between a reflected wave, which isradiated from the slot 75, is reflected at the boundary between thedielectric layer 72 and the waveguide 76, is again reflected at theinternal ground conductor layer 78, and is again returned to theboundary between the dielectric layer 72 and the waveguide 76 and adirect wave directly transmitted from the slot 75 to the boundarybetween the dielectric layer 72 and the waveguide 76 becomes the sum ofapproximately ½ of the wavelength of the electromagnetic wave and anintegral multiple of the wavelength of the electromagnetic wave, andwhen the reflected wave is reflected at the boundary between thedielectric layer 72 and the waveguide 76, the phase of the magneticfield is inverted, and accordingly, at the boundary between thedielectric layer 72 and the waveguide 76, the direct wave and thereflected wave come to have the same phase and intensify each other, andthe signal is efficiently transmitted to the waveguide.

Besides, when the area of the transmission opening 79 is made the halfor less of the area of the region surrounded by the shield conductorpart 77, the internal ground conductor layer 78 occupies the half ormore of the area of the region surrounded by the shield conductor part77, the half or more of the reflected wave radiated from the slot 75 andreflected at the boundary between the dielectric layer 72 and thewaveguide 76 is again reflected at the internal ground conductor layer78, and this reflected wave and the direct wave from the slot 75 come tohave the same phase and intensify each other, and eventually, thetransmission opening 79 enhances the conversion efficiency of the highfrequency line-to-waveguide converter.

Besides, when the shield conductor part 77 is constituted by theplurality of through conductors, at the time of fabrication of the highfrequency line-to-waveguide converter, it becomes possible to form thethrough conductors at the same time as the line conductor 73, the groundconductor layer 74, and the internal ground conductor layer 78, and thehigh frequency line-to-waveguide converter can be easily fabricated.

Besides, as exemplified in a plan view of a line conductor 73 a of FIG.8A, when a tip of the line conductor 73 a of the high frequency line 71a is opened, and a distance between this open tip and substantially thecenter part of the slot 75 is made approximately (2n−1)/4 (n is anatural number) of a signal wavelength, an optical path length of areflected wave transmitted from substantially the center part of theslot 75 to the open tip, totally reflected at the open tip, and returnedto substantially the center part of the slot 75 becomes the sum ofapproximately ½ of the signal wavelength and an integral multiple of thesignal wavelength, and further, the phase of the magnetic field isinverted by the total reflection at the open tip and eventually, thisreflected wave and the high frequency signal transmitted through thehigh frequency line 71 a come to have the same phase and intensify eachother to be highly coupled to the slot 75, and the conversion efficiencyfrom the high frequency line to the waveguide can be enhanced.

Besides, as exemplified in a plan view of a line conductor 73 b of FIG.8B, when a tip of the line conductor 73 b of a high frequency line 71 bis short-circuited, and a distance between this short-circuit tip andsubstantially the center part of a slot 75 of the line conductor 73 b ismade approximately (n−1)/2 (n is a natural number) of a signalwavelength, an optical path length of a reflected wave transmitted fromsubstantially the center part of the slot 75 to the short-circuit tip,totally reflected at the short-circuit tip, and returned tosubstantially the center part of the slot 75 becomes an integralmultiple of the signal wavelength, and the phase of a magnetic field isnot changed by the total reflection at the short-circuit tip, andaccordingly, this reflected wave and the high frequency signaltransmitted through the high frequency line 71 b come to have the samephase and intensify each other to be highly coupled to the slot 75, andthe conversion efficiency from the high frequency line 71 b to thewaveguide 76 can be enhanced.

Incidentally, FIG. 8C is a plan view exemplifying a line conductor 73 cin a case where n is 1 in the example in which the tip of the lineconductor 73 c is short-circuited. The tip of the line conductor isshort-circuited in the slot part, and the reflection by the shortcircuit does not change the phase of a magnetic field, so that thereflected wave and the high frequency signal transmitted through thehigh frequency line come to have the same phase and intensify each otherto be highly coupled to the slot 75, and the conversion efficiency fromthe high frequency line 71 c to the waveguide 76 can be enhanced.

Besides, when the ground conductor layer 74 of the high frequency line71 and the internal ground conductor layer 78 are connected through theconnection conductor 80 along the transmission opening 79, it becomespossible to effectively use a region by mounting, for example, a highfrequency element onto a portion of the high frequency line 71 outsideof the region surrounded by the connection conductor 80, and as aresult, a system using the high frequency line-to-waveguide convertercan be miniaturized.

A dielectric material forming the dielectric layer 72 is the same as thedielectric layer 42 and 52 of the above-mentioned embodiment and thedetailed explanation will be omitted.

As a conductor material forming the line conductor 73, the groundconductor layer 74, the shield conductor part 77 of the throughconductor or the like, the internal ground conductor layer 78, and theconnection conductor 80, a metalized material containing tungsten,molybdenum, gold, silver, copper or the like as its main ingredient, ora metal foil containing gold, silver, copper, aluminum or the like asits main ingredient is used.

Especially in the case where the high frequency line-to-waveguideconverter is incorporated in a wiring substrate on which a highfrequency component is mounted, as a dielectric material forming thedielectric layer 72, like the above-mentioned embodiment, it isdesirable that a dielectric loss tangent is small, and airtight sealingis possible. As an especially desirable dielectric material, at leastone kind of inorganic material selected from a group consisting ofaluminum oxide aluminum nitride, and glass ceramic material can bementioned. When such a hard material is used, the dielectric losstangent is small and the mounted high frequency component can beairtightly sealed, so that such a material is preferable in raising thereliability of the mounted high frequency component. In this case, as aconductor material, it is desirable in view of airtightness andproductivity to use a metalized conductor which can be fired at the sametime as the dielectric material.

The high frequency line-to-waveguide converter of the invention isfabricated as described below. For example, in the case where analuminum oxide sintered body is used as the dielectric material, first,a suitable organic solvent is added to and mixed with a raw materialpowder of aluminum oxide, silicon oxide, magnesium oxide, calcium oxideor the like to form slurry, and this is formed into a sheet by awell-known doctor blade method or a calender roll method to fabricate aceramic green sheet. Besides, a suitable organic solvent is added to andmixed with a raw material powder of high melting metal, such as tungstenor molybdenum, aluminum oxide, silicon oxide, magnesium oxide, calciumoxide or the like to fabricate a metallization paste. Next, throughholes for formation of through conductors as the shield conductor parts77 and the connection conductor 80 are formed in the ceramic green sheetby, for example, a punching method, and the metallization paste isimplanted in the through holes by, for example, a printing method, andsubsequently, the metallization paste is printed to have the shape ofthe ground conductor 74 and the internal ground conductor layer 78having the line conductor 73 and the slot 75. In the case where thedielectric layer 72 is made of a laminate structure having a pluralityof dielectric layers, ceramic green sheets in which these conductors areimplanted and printed are laminated, are pressurized to be subjected topressure bonding, and are fired at a high temperature (about 1600° C.).Further, the surface of the conductor exposed on the surface of the lineconductor 73, the ground conductor 74 or the like is plated with nickeland gold.

The shield conductor parts 77 are disposed on the side of or in theinside of the dielectric layer 72 so as to surround the one end of theline conductor 73 and the slot 75, and are electrically connected to theground conductor layer 74 to be grounded.

The connection conductor 80 is disposed in the dielectric layer 72 so asto surround the transmission opening 79, and electrically connects theground conductor layer 74 and the internal ground conductor layer 78.

It is desirable that a gap (indicated by G1 in FIG. 6A) between theconnection conductors 80 is made less than ¼ of the wavelength of theelectromagnetic wave in the dielectric layer 72. This is because whenthe gap is made less than ¼ of the wavelength of the electromagneticwave, the electromagnetic wave becomes difficult to leak from the gapbetween the connection conductors, so that the electromagnetic wavebecomes difficult to leak to the outside region surrounded by theconnection conductors 80 sandwiched between the ground conductor layer74 and the internal ground conductor layer 78, and the occurrence of aparallel-plate mode as an unnecessary mode which can occur in thisregion can be suppressed.

Incidentally, the through conductor constituting the connectionconductor 80 and the through conductor constituting the shield conductor77 have only to electrically connect the ground conductor layer 74 andthe internal ground conductor layer 78 or the waveguide connectionconductor 81, and it may be a so-called through hole conductor in whichthe inner wall of a through hole is coated with a conductor layer, ormay be a so-called via conductor in which the inside of a through holeis filled with a conductor.

It is preferable that a distance between the internal ground conductorlayer 78 and the waveguide 76 is made approximately ¼ of the wavelengthof the electromagnetic wave excited in the dielectric layer 72 by thesignal transmitted through the high frequency line 71 in order toenhance the conversion efficiency of the high frequencyline-to-waveguide conversion. When the distance between the internalground conductor layer 78 and the waveguide 76 is made approximately ¼of the wavelength of the electromagnetic wave, since an optical pathlength in which a reflected wave reflected at the boundary between thedielectric layer 72 and the waveguide 76 is totally reflected at theinternal ground conductor layer 78 and is returned to the boundarybecomes approximately ½ of the wavelength of the electromagnetic wave,the phase is inverted when the reflected wave is returned, and further,the phase is inverted by the total reflection at the internal groundconductor layer 78. Thus, the reflected wave comes to have the samephase as the direct wave directly transmitted to the boundary betweenthe dielectric layer 72 and the waveguide 76 from the slot 75, and theseare combined with each other, and the signal is efficiently transmittedto the waveguide 76. Incidentally, when the distance between theinternal ground conductor layer 78 and the waveguide 76 is made (2n−1)/4of the wavelength of the electromagnetic wave, where n is a naturalnumber, the optical path difference between the reflected wave and thedirect wave becomes substantially ½ of the wavelength of theelectromagnetic wave, and the same effect as the above is exerted, andfurther, the frequency becomes high, and the wavelength of theelectromagnetic wave becomes short, and in order to set the distancebetween the internal ground conductor layer 78 and the waveguide 76 to ¼of the wavelength of the electromagnetic wave, the thickness of thedielectric layer 72 must be made thin, and in the case where thestrength of the dielectric layer is lowered, the distance between theinternal ground conductor layer 78 and the waveguide 76 is made ¾, 5/4or the like of the signal wavelength, so that it is possible to suppressthe lowering of the strength of the dielectric layer 72.

The distance between the internal ground conductor layer 78 and thewaveguide 76 can be adjusted in the foregoing fabrication method, byadjusting the thickness of the ceramic green sheet which becomes thedielectric layer 72 after firing. In this case, the adjustment may bemade by the thickness of one ceramic green sheet, or the adjustment maybe made by laminating a plurality of ceramic green sheets.

The coupling of the high frequency line 71 and the slot 75 is notparticularly restricted, and for example, as shown in FIG. 6A, the tipof the high frequency line 71 may be short-circuited and coupled to theground conductor layer 74, and in this case, when the distance betweenthe short-circuit tip of the high frequency line 71 and substantiallythe center part of the slot 75 is set to approximately (n−1)/2 of thesignal wavelength, where n is a natural number, in a standing waveformed by synthesis of a traveling wave transmitted through the highfrequency line and a reflected wave reflected at the short-circuitedtip, a magnetic field becomes highest at substantially the center partof the slot 75, electromagnetic coupling from the high frequency line 71to the slot 75 through the magnetic field is performed most excellently,and the conversion efficiency of the high frequency line-to-waveguideconverter can be enhanced.

Besides, in the case where the tip of the high frequency line 71 isopened, when the distance between the opened tip and substantially thecenter of the slot 75 is set to approximately (2n−1)/4 of the signalwavelength, where n is a natural number, in a standing wave formed bysynthesis of a traveling wave transmitting through the high frequencyline 71 and a reflected wave reflected at the opened tip, a magneticfield becomes highest substantially at the center part of the slot 75,electromagnetic coupling from the coplanar line to the slot 75 throughthe magnetic field is performed most excellently, and the conversionefficiency of the high frequency line-to-waveguide converter can beraised.

The shape of the waveguide 76 is not particularly restricted, and forexample, when the WR series regulated as a rectangular waveguide isused, since a measurement correction kit is substantial, variouscharacteristic evaluations become easy. However, according to thefrequency of a high frequency signal to be used, for miniaturization andreduction in weight of a system, a miniaturized rectangular waveguidemay be used within the range where cutoff of the waveguide does notoccur. Besides, a circular waveguide may be used.

The waveguide 76 is the same as the waveguide 46 of the above-mentionedembodiment and the detailed explanation will be omitted.

To attach the waveguide 76 to the high frequency line-to-waveguideconverter by joining with solder material is the same as theabove-mentioned embodiment and the detailed explanation will be omitted.

The waveguide connection conductor 81 may be simultaneously formed, inthe foregoing fabrication method, by printing metallization paste intothe shape of the waveguide connection conductor 81 similarly to theformation of the line conductor 73, the ground conductor layer 74 andthe internal ground conductor layer 78. Further, similarly to theconductor exposed on the surface, such as the line conductor 73 and theground conductor layer 74, when the surface is plated with nickel andgold, the wettability of the solder material in the case of the joiningwith the solder material is improved, and according, this is moredesirable.

Incidentally, the invention is not limited to the above examples of theembodiment, and various modifications may be performed within the scopeof the gist of the invention.

For example, although FIGS. 6A and 6B show the examples in which thehigh frequency line has the coplanar line structure, a coplanar linestructure having a ground may be adopted in which a dielectric layer 72a is further laminated on the dielectric layer 72, and an upper groundconductor layer 74 a is provided on the upper surface of the dielectriclayer 72 a so as to cover the line conductor 73, as shown in FIG. 6C. Inany case, when the positional relation among the dielectric layer 72,the line conductor 73, the ground conductor layer 74, the slot 75, thewaveguide 76, the shield part 77 and the internal ground conductor layer78 is made the same as the example shown in FIGS. 6A and 6B, the sameeffect can be obtained.

Besides, for example, the width of the line conductor 73 is changedbetween the tip of the line conductor 73 and the slot 75 to change aneffective dielectric constant, and the distance between the tip of theline conductor and the slot can also be made approximately (n−1)/2 ofthe wavelength of the signal to be transmitted in the case of a shortcircuit, or approximately (2n−1)/4 of the wavelength of the signal to betransmitted in the case of an open circuit.

EXAMPLE

Next, in order to confirm the effect of the high frequencyline-to-waveguide converter of the invention, an experiment as describedbelow was carried out.

First, by using a ceramic green sheet of alumina ceramic whosedielectric loss tangent at 10 GHz became 0.0006 after firing and ametallization paste for tungsten metallization, an evaluation substrateas shown in FIGS. 9A to 9C was fabricated by a normal green sheetlamination technique and a simultaneous firing technique. Incidentally,FIG. 9A is a top view of the evaluation substrate, FIG. 9B is asectional view taken along line VII-VII of FIG. 9A, and FIG. 9C is abottom view.

After firing, the surfaces of respective metallized layers of the uppersurface and the lower surface of the evaluation substrate were subjectedto plating with nickel and gold. Here, with respect to the highfrequency line-to-waveguide converter in the evaluation substrate, thecorresponding waveguide was set to a WR-10 for a W band (75 GHz to 110GHz), and was designed while 76 GHz was made the center frequency. Theevaluation substrate includes two high frequency line-to-waveguideconverters of the invention at both sides in the drawing, each includingthe dielectric layer 72, the line conductor 73, the ground conductorlayer 74, the slot 75, the shield conductor part 77 made of the shieldthrough conductors, the internal ground conductor layer 78, thetransmission opening 79, the connection conductor 80, and the waveguideconnection conductor 81 as shown in FIGS. 6A and 6B, and these twoconverters have such a structure that the line conductors 73, the groundconductor layers 74, and the internal ground conductor layers 78 of bothare respectively integrated. The integrated line conductor 73 and groundconductor layer 74, together with the dielectric layer 72, constitutethe connection coplanar line 86. The interval between the high frequencyline-to-waveguide converters at both sides was made 20 mm so thatmeasuring waveguides could be respectively connected. By this, theevaluation substrate has such a structure that the two high frequencyline-to-waveguide converters are connected by the connection coplanarline 86 having a length of 20 mm.

Next, a reflection within the range of 75 GHz to 110 GHz was measured bya method in which a waveguide opening of a measuring waveguide was madeto conform to the waveguide connecting conductor 81 of each of the highfrequency line-to-waveguide converters of this evaluation substrate andwas connected by screwing, a signal was inputted from one of thewaveguides, and the signal outputted from the other of the waveguideswas measured.

As a result, the reflection at 76 GHz was −16 dB, a steep reflectionpeak occurring by an unnecessary mode in a pass band was not recognized,and an excellent conversion characteristic was exhibited. Besides, theband of the reflection of −15 dB was 75 GHz to 84 GHz, the band widthwas 9 GHz, and a relatively broad band characteristic was exhibited.

FIGS. 10A and 10B are views showing a high frequency package accordingto still another embodiment of the invention, in which FIG. 10A is aplan view, and FIG. 10B is a sectional view taken along line VIII-VIIIof FIG. 10A. In FIGS. 10A and 10B, reference numeral 101 denotes a highfrequency electronic component; reference numeral 102 denotes a mountingpart; reference numeral 103 denotes a metal base; reference numeral 104denotes a waveguide; reference numeral 105 denotes a through hole;reference numeral 106 denotes a dielectric substrate; reference numeral107 denotes a high frequency line conductor; reference numeral 108denotes a same surface ground conductor; reference numeral 109 denotes aconnection terminal part; reference numeral 110 denotes a frame groundconductor; reference numeral 111 denotes a slot; reference numeral 112denotes an internal ground conductor; reference numeral 113 denotes afirst connection conductor; reference numeral 114 denotes a secondconnection conductor; and reference numeral 115 denotes a conversionsubstrate.

In an example of a high frequency package of the invention, a throughhole 105 disposed to be adjacent to a mounting part 102 and having alower side opening connected with a waveguide 104 is formed in a metalbase 103 having the mounting part 102 for a high frequency electroniccomponent 101 on an upper surface, a connection terminal part 109including a high frequency line conductor 107 directed from an outerperipheral part to a center part on an upper surface of a dielectricsubstrate 106 and a same surface ground conductor 108 disposed to beclose to the high frequency line conductor 107 is formed at an upperside of the through hole 105, a frame ground conductor 110 having ashape conforming to an upper side opening of the through hole 105 isformed on the lower surface of the dielectric substrate 106 so as to beopposite to an end of the high frequency line conductor 107 on thecenter part side, an internal ground conductor 112 provided with a slot111 coupled with the end of the high frequency line conductor 107 on thecenter part side in terms of high frequency is formed between the end ofthe high frequency line conductor 107 on the center part side in theinside of the dielectric substrate 106 and the frame ground conductor110. A conversion substrate 115 in which the same surface groundconductor 108 is connected to the internal ground conductor 112 througha first connection conductor 113 and the frame ground conductor 110 isconnected to the internal ground conductor 112 through a secondconnection conductor 114, is jointed on the upper side of the throughhole 105 of the metal base 103 such that the connection terminal part109 is positioned on a side of the mounting part 102 and the frameground conductor 110 is made to conform to the upper side opening of thethrough hole 105.

That is, the high frequency package according to the embodiment of theinvention comprises a metal base 103 and the conversion substrate 115.The metal base 103 has the mounting part 102 for the high frequencyelectronic component 101 on the upper surface thereof the through hole105 disposed to be adjacent to the mounting part 102 and having thelower side opening connected with the waveguide 104, is formed in themetal base 103.

The conversion substrate 115 has the dielectric substrate 106, theconnection terminal part 109, the frame ground conductor 110, theinternal ground conductor 112, the first connection conductor 113 andthe second connection conductor 114. The connection terminal part 109includes the high frequency line conductor 107 disposed so as to extendfrom the outer peripheral part toward the center part on the uppersurface of the dielectric substrate 106, and the same surface groundconductor 108 disposed to be close to the high frequency line conductor107 on the upper surface of the dielectric substrate 106.

The frame ground conductor 110 is formed on the lower surface of thedielectric substrate 106 in a shape conforming to the upper side openingof the through hole 105 so as to be opposite to the end of the highfrequency line conductor 107 on the center part side. The internalground conductor 112 is formed in the inside of the dielectric substrate106 and between the end of the high frequency line conductor 107 on thecenter part side and the frame ground conductor 110. The internal groundconductor 112 is provided with a slot 111 coupled with the end of thehigh frequency line conductor 107 on the center part side in terms ofhigh frequency. The first connection conductor 113 connects the samesurface ground conductor 108 and the internal ground conductor 112. Thesecond connection conductor 114 connects the frame ground conductor 110and the internal ground conductor 112.

The conversion substrate 115 is jointed on the upper side of the throughhole 105 of the metal base 103 such that the connection terminal part109 is positioned on the side of the mounting part 102 of the metal base103 and the frame ground conductor 110 is made to conform to the upperside opening of the through hole 105 of the metal base 103.

By adopting the structure as stated above, the conversion substrate 115and the high frequency electronic component 101 are separatelyfabricated, and subsequently, the ground of the conversion substrate 115and the ground of the high frequency electronic component 101 can beconnected by wire bonding from the outside, and contrary to the relatedart, it is not necessary to extend the internal ground conductor 112 ofthe conversion substrate 115, to provide the mounting part of the highfrequency electronic component 101 formed to be exposed on the surface,and to previously internally connect the ground of the conversionsubstrate 115 and the ground of the high frequency electronic component101 by the internal ground conductor 112. Thus, the conversion substrate115 can be miniaturized, and a thermal expansion mismatch between theconversion substrate 115 and the metal base 103 in the manufacturingprocess of the high frequency package can be made small, so that thewarp or crack of the package can be prevented.

Besides, when the high frequency line conductor 107 of the conversionsubstrate 115 is connected to the high frequency line conductor of thehigh frequency electronic component 101 by wire bonding, and the samesurface ground conductor 108 of the conversion substrate 115 is bondedto the ground conductor of the high frequency electronic component 101by wire bonding, the connection distance between the high frequency lineconductors and the connection distance between the same surface groundconductors can be made substantially the same distance, and transmissionbecomes possible without causing a difference between the phase of thesignal potential of the high frequency signal and the phase of theground potential in the connection part of both, and excellenttransmission of the high frequency signal becomes possible.

On the other hand, in the case where the conversion substrate 115 doesnot have the same surface ground conductor 108, although the highfrequency line conductor 107 of the conversion substrate 115 and thehigh frequency line conductor of the high frequency electronic component101 are connected by wire at a relatively short distance, a highfrequency signal reaches the internal ground conductor 112, which givesthe ground potential of a high frequency signal transmitted through thehigh frequency line conductor 107 of the conversion substrate 115, fromthe mounting part 102 as the ground part of the high frequencyelectronic component 101 through the metal base 103, the frame conductor110, and the second connection conductor 114, and the distance becomesvery long as compared with the connection distance between the highfrequency line conductors, the phase of the ground potential in the highfrequency electronic component 101 becomes later than the phase of thesignal potential by the extended length of the connection distance, andthere is a case where the high frequency signal can not be excellentlytransmitted.

In the structure of the conventional high frequency line-to-waveguideconverter, the high frequency electronic component 101 is mounted on theportion where the internal ground conductor 112 of the high frequencyline-to-waveguide converter is extended and exposed on the surface, andthe ground potential of the high frequency electronic component 101 isdirectly transmitted to the high frequency line-to-waveguide converterby the internal ground conductor 112, so that the delay to the signalpotential hardly occurs, and it is not necessary to provide the samesurface ground conductor layer 108 on the upper surface of theconversion substrate 115 and to make connection. However, in this case,it is necessary that the internal ground conductor 112 of the dielectricsubstrate 106 is extended to be exposed on the surface, and the mountingpart for mounting of the high frequency electronic component 101 isintegrally formed with the high frequency line-to-waveguide converter,and accordingly, the dielectric substrate 106 becomes large, and thereis a case where the warp or crack occurs at the joining to the metalbase 103. In the high frequency package of the invention, the samesurface ground conductor 108 is formed on the conversion substrate 115,so that the connection of the grounds of the conversion substrate 115and the high frequency electronic component 101 can also be performed bywire bonding, and it becomes unnecessary to provide the mounting part ofthe high frequency electronic component 101 which is formed by extendingthe internal ground conductor 112 of the conversion substrate 15 andexposing it on the surface, the conversion substrate 115 isminiaturized, and the warp or crack at the joining to the metal base 103can be suppressed.

Besides, in the high frequency package of the invention, when theinterval between the high frequency line conductor 107 and the samesurface ground conductor layer 108 is made ¼ or less of the signalwavelength of the high frequency signal transmitted through the highfrequency line conductor 107, in the case where the high frequency lineconductor 107 of the conversion substrate 115 and the high frequencyline conductor of the high frequency electronic component 101, and thesame surface ground conductor 108 of the conversion substrate 115 andthe same surface ground conductor of the high frequency electroniccomponent 101 are respectively connected by wire bonding, the distancebetween the wire for connecting the high frequency line conductors andthe wire for connecting the same surface ground conductors can be madeapproximately ¼ or less of the signal wavelength of the high frequencysignal, the respective wires are electromagnetically coupled to eachother to form a high frequency transmission path, and the high frequencypackage excellent in transmission of the high frequency signal can beprovided.

Besides, in the high frequency package of the invention, in the casewhere the same surface ground conductor 108 is disposed at both sides ofthe high frequency line conductor 107, the wire for connecting the highfrequency line conductors of the conversion substrate 115 and the highfrequency electronic component 101 and the wire for connecting theground conductor of them are coupled to each other and transmit the highfrequency signal as a high frequency transmission path of a signaltransmission principle similar to the coplanar line, and the highfrequency package excellent in transmission of the high frequency signalcan be provided.

Besides, in the high frequency package of the invention, since theconversion substrate 115 is joined to the metal base 103 having themounting part 102 of the high frequency electronic component 101, thehigh frequency electronic component 101 is directly connected to themetal base 103, and heat generation due to the operation of the highfrequency electronic component 101 can be dissipated through the metalbase 103, and the high frequency package excellent in thermaldissipation can be provided.

Since the same surface ground conductor 108 is connected to the internalground conductor 112 through the first connection conductor 113, thehigh, frequency signal is transmitted from the outer peripheral part ofthe high frequency line conductor 107 toward the center part of thedielectric substrate 106 along the internal ground conductor 112, and istransmitted through the slot 111, which is provided to be coupled withthe end of the high frequency line conductor 107 on the center part sideof the dielectric substrate 106 in terms of high frequency, to thethrough hole 105 to which the lower side waveguide 104 is connected. Theinternal ground conductor 112 provided with the slot 111 is connected tothe frame ground conductor 110 through the second connection conductor114, and the high frequency signal is transmitted to the waveguide 104.

Here, when the length (slot length) of the slot 111 in the directionorthogonal to the high frequency line conductor 107 is generally madeapproximately ½ of the high frequency signal wavelength so that the slot111 is coupled with the high frequency line conductor 107 in terms ofhigh frequency, a standing wave in which magnetic field intensity at thecenter part of the slot 111 becomes maximum occurs in the slot 111, andcoupling efficiency by the magnetic field to the high frequency lineconductor 107 is increased. Besides, when the distance between theinternal ground conductor 112 and the frame ground conductor layer 110is made approximately ¼ of the high frequency signal in the dielectricsubstrate 106 or odd number times as long as that, the phase of a directwave radiated from the slot 111 and directly transmitted from thedielectric substrate 106 to the waveguide 104 becomes equal to the phaseof a reflected wave reflected at the boundary between the dielectricsubstrate 106 and the waveguide 104, again reflected at the internalground conductor 112 and reaching the boundary between the dielectricsubstrate 106 and the waveguide 104, and they intensify each other, sothat the coupling efficiency of the slot 111 and the waveguide 104 isincreased.

FIGS. 11A and 11B are views showing a high frequency package accordingto still another embodiment of the invention, in which FIG. 11A is aplan view, and FIG. 11B is a sectional view taken along line IX-IX ofFIG. 11A. In FIGS. 11A and 11B, reference numeral 120 denotes a highfrequency electronic component; reference numeral 121 denotes a mountingpart; 122 reference numeral denotes a metal base; reference numeral 123denotes a waveguide; reference numeral 124 denotes a through hole;reference numeral 125 denotes a dielectric substrate; reference numeral126 denotes a high frequency line conductor; reference numeral 127denotes a same surface ground conductor; reference numeral 128 denotes aconnection terminal part; reference numeral 129 denotes a frame groundconductor; reference numeral 130 denotes a slot; reference numeral 131denotes a connection conductor; and reference numeral 132 denotes aconversion substrate.

In the example of the high frequency package of the invention, a throughhole 124 disposed to be adjacent to a mounting part 121 and having alower side opening connected with a waveguide 123 is formed in a metalbase 122 having the mounting part 121 for a high frequency electroniccomponent 120 on an upper surface, a connection terminal part 128including a high frequency line conductor 126 directed from an outerperipheral part to a center part on an upper surface of a dielectricsubstrate 125 and a same surface ground conductor 127 disposed on thesame surface so as to surround an end of the high frequency lineconductor 126 on the center part side is formed at an upper side of thethrough hole 124, a frame ground conductor 129 having a shape conformingto an upper side opening of the through hole 124 is formed on a lowersurface of the dielectric substrate 125 so as to be opposite to the endof the high frequency line conductor 126 on the center part side, a slot130 formed to be orthogonal to the end of the high frequency lineconductor 126 on the center part side and coupled with the highfrequency line conductor 126 in terms of high frequency is provided inthe same surface ground conductor 127. A conversion substrate 132 inwhich the same surface ground conductor 127 is connected to the frameground conductor 129 through a connection conductor 131 is joined on theupper side of the through hole 124 such that the connection terminalpart 128 is positioned one a side of the mounting part 121 and the frameground conductor 129 is made to conform to an upper side opening of thethrough hole 124.

That is, the high frequency package according to the embodiment of theinvention comprises the metal base 122 and the conversion substrate 132.The metal base 122 has the mounting part 121 for the high frequencyelectric component 120 on the upper surface thereof. The through hole124 disposed to be adjacent to the mounting part 121 and having thelower side opening connected with the waveguide 123, is formed in themetal base 122.

The conversion substrate 132 has the dielectric substrate 125, theconnection terminal part 128, the frame ground conductor 129 and theconnection conductor 131. The connection terminal conductor 128 includesthe high frequency line conductor 126 formed on the upper surface of thedielectric substrate 125 and disposed so as to extend from the outerperipheral part toward the center part on the upper surface of thedielectric substrate 125, and the same surface ground conductor 127disposed on the same surface as the upper surface of the dielectricsubstrate 12S so as to surround the end of the high frequency lineconductor 126 on the center part side. The same surface ground conductor127 is provided with the slot 130 formed to be orthogonal to the end ofthe high frequency line conductor 126 on the center part side andcoupled with the high frequency line conductor 126 in terms of highfrequency.

The frame ground conductor 129 is formed on the lower surface of thedielectric substrate 125 in a shape conforming to the upper side openingof the through hole 124 so as to be opposite to the end of the highfrequency line conductor 126 on the center part side. The connectionconductor 131 connects the same surface ground conductor 127 and theframe ground conductor 129.

The conversion substrate 132 is joined on the upper side of the throughhole 124 of the metal base 122 such that the connection terminal part128 is positioned on the side of the mounting part 121 of the metal base122 and the frame ground conductor 129 is made to conform to the upperside opening of the through hole 124 of the metal base 122.

By adopting the structure as stated above, it becomes possible toconnect the ground of the conversion substrate 132 and the ground of thehigh frequency electronic component 120 by wire bonding, and it is notnecessary to provide the mounting part, which is formed by extending thedielectric substrate 125, of the high frequency electronic component 120as in the related art, and the conversion substrate 132 can beminiaturized, and a thermal expansion mismatch between the conversionsubstrate 132 and the metal base 122 in the manufacture process of thehigh frequency package can be made small, so that the warp or crack ofthe package can be prevented.

Besides, when the high frequency line conductor 126 of the conversionsubstrate 132 is connected to the high frequency line conductor of thehigh frequency electronic component 120 by wire bonding, and the samesurface ground conductor 127 of the conversion substrate 132 is bondedto the ground conductor of the high frequency electronic component 120by wire bonding, the connection distance between the high frequency lineconductors and the connection distance between the same surface groundconductors can be made substantially the same distance, and transmissionbecomes possible without causing a difference between the phase of thesignal potential of the high frequency signal and the phase of theground potential in the connection part of both, and excellenttransmission of the high frequency signal becomes possible.

Besides, in the high frequency package of the invention, when theinterval between the high frequency line conductor 126 and the samesurface ground conductor layer 127 is made ¼ or less of the signalwavelength of the high frequency signal transmitted through the highfrequency line conductor 126, in the case where the high frequency lineconductor 126 of the conversion substrate 132 and the high frequencyline conductor of the high frequency electronic component 120, and thesame surface ground conductor 127 of the conversion substrate 132 andthe same surface ground conductor of the high frequency electroniccomponent 120 are respectively connected by wire bonding, the distancebetween the wire for connecting the high frequency line conductors andthe wire for connecting the same surface ground conductors can be madeapproximately ¼ or less of the signal wavelength of the high frequencysignal, the respective wires are electromagnetically coupled to eachother to form a high frequency transmission path, and the high frequencypackage excellent in transmission of the high frequency signal can beprovided.

Besides, in the high frequency package of the invention, since thecoplanar line made of the high frequency line conductor 126 and the samesurface ground conductor 127 is used as the high frequency line on theupper surface of the conversion substrate 132, when the high frequencyline conductor 126 of the conversion substrate 132 and the highfrequency line conductor of the high frequency electronic component 120,and the same surface ground conductor layer 127 and the sample surfaceground conductor of the high frequency electronic component 120 arerespectively connected to each other by wire bonding, since the groundpotential of the same surface ground conductor of the high frequencyelectronic component 120 is directly transmitted by wire to the samesurface ground conductor 127 of the coplanar line of the conversionsubstrate 132, so that it is possible to provide the high frequencypackage which has no delay for transmission of the signal potential ofthe high frequency line conductor of the high frequency electroniccomponent 120 and is excellent in transmission of the high frequencysignal.

Besides, in the high frequency package of the invention, the slot 130playing an important role when the high frequency line on the uppersurface of the conversion substrate 132 is converted to the waveguide123 is formed on the upper surface of the conversion substrate 132. Thelength and width of this slot 130 influences the conversion efficiencyin conversion of the high frequency line to the waveguide 123, and whenthe length of the slot 130 is made approximately ½ of the high frequencysignal wavelength, a standing wave in which magnetic field intensity atthe center part of the slot 130 becomes maximum occurs in the slot 130,and the coupling efficiency to the high frequency line by the magneticfield is enhanced. When the width of the slot 130 is formed to haveimpedance equal to impedance of the high frequency line, the impedancemismatch between the high frequency line and the slot 130 is eliminatedand the coupling efficiency to the high frequency line at the signalfrequency is enhanced.

Besides, when the width of the slot 130 is formed to have impedancelarger than impedance of the high frequency line, a state at the signalfrequency deviates from the impedance matching state, and the couplingefficiency to the high frequency line is slightly decreased. However,even if the frequency is changed in the vicinity of the signalfrequency, the phase of the impedance mismatch is merely changed, andthe magnitude of the impedance mismatch is not changed much, and thecoupling is performed while the state where the coupling efficiency tothe high frequency line is high is kept, so that the frequency band isbroadened.

Besides, by adopting the package of this structure, it becomes possibleto check the size of the slot from the outside, and it is possible toprovide the high frequency package in which the high frequencyline-to-waveguide conversion efficiency is excellent.

The high frequency signal converted from the high frequency line by theslot 130 is transmitted to the waveguide 123 similarly to the example ofthe embodiment of the invention. When the distance between the samesurface ground conductor 127, the high frequency line conductor 126 andthe frame ground conductor 129 is set to approximately ¼ of or oddnumber times as long as the high frequency signal wavelength in thedielectric substrate 125, the phase of a direct wave radiated from theslot 130 and directly transmitted from the dielectric substrate 125 tothe waveguide 123 becomes identical to the phase of a reflected wavereflected at the boundary between the dielectric substrate 125 and thewaveguide 123, again reflected at the same surface ground conductor 127,and having reached the boundary between the dielectric substrate 125 andthe waveguide 123, and they intensify each other, so that the highfrequency signal is efficiently converted and transmitted to thewaveguide.

FIGS. 12A and 12B are views showing a high frequency package accordingto still another embodiment of the invention, in which FIG. 12A is aplan view, and FIG. 12B is a sectional view taken along line X-X of FIG.12A. In FIGS. 12A and 12B, reference numeral 140 denotes a highfrequency electronic component; reference numeral 141 denotes a secondhigh frequency electronic component; reference numeral 142 denotes amounting part; reference numeral 143 denotes a metal base; referencenumeral 144 denotes a waveguide; reference numeral 145 denotes a throughhole; reference numeral 146 denotes a dielectric substrate; referencenumeral 147 denotes a high frequency line conductor; reference numeral148 denotes a same surface ground conductor; reference numeral 149denotes a connection terminal part; reference numeral 150 denotes aframe ground conductor; reference numeral 151 denotes a slot; referencenumeral 152 denotes a transmission opening; reference numeral 153denotes an internal ground conductor; reference numeral 154 denotes afirst connection conductor; reference numeral 155 denotes a secondconnection conductor; and reference numeral 156 denotes a conversionsubstrate.

In the example of the high frequency package of the invention, a throughhole 145 disposed to be adjacent to a mounting part 142 and having alower side opening connected with a waveguide 144 is formed in a metalbase 143 having the mounting part 142 for a high frequency electroniccomponent 140 and 141 on an upper surface, a connection terminal part149 including a high frequency line conductor 147 directed from an outerperipheral part to a center part on an upper surface of a dielectricsubstrate 146 and a same surface ground conductor 148 disposed on thesame surface so as to surround an end of the high frequency lineconductor 147 on the center part side is formed at an upper side of thethrough hole 145, a frame ground conductor 150 having a shape conformingto an upper side opening of the through hole 145 is formed on a lowersurface of the dielectric substrate 146 so as to be opposite to the endof the high frequency line conductor 147 on the center part side, a slot151 formed to be orthogonal to the end of the high frequency lineconductor 147 on the center part side and coupled with the highfrequency line conductor 147 in terms of high frequency is provided inthe same surface ground conductor 148, and the internal ground conductor153 provided with the transmission opening 152 opposite to the slot 151and larger than the slot 151 is formed between the high frequency lineconductor 147 of the inside of the dielectric substrate 146 and theframe ground conductor 150, and the conversion substrate 156 in whichthe same surface ground conductor 148 is connected to the internalground conductor 153 through the first connection conductor 154 and theframe ground conductor 150 is connected to the internal ground conductor153 through the second connection conductor 155, is joined on the upperside of the through hole 145 such that the frame ground conductor 150 ismade to conform to the upper opening of the through hole 145.

That is, the high frequency package according to the embodiment of theinvention comprises the metal base 143 and the conversion substrate 156.The metal base 143 has the mounting part 142 for high frequency electriccomponent 140 and 141 at the upper surface thereof. The through hole 145disposed to be adjacent to the mounting part 142 and having the lowerside opening connected with the waveguide 144, is formed in the metalbase 143.

The conversion substrate 156 has the dielectric substrate 146, theconnection terminal part 149, the frame ground conductor 150, theinternal ground conductor 153, the first connection conductor 154 andthe second connection conductor 155. The connection terminal part 149includes the high frequency line conductor 147 disposed so as to extendfrom the outer peripheral part toward the center part on the uppersurface of the dielectric substrate 146, and the same surface groundconductor 148 disposed on the same surface as the upper surface of thedielectric substrate 146 so as to surround the end of the high frequencyline conductor 147 on the center part side. The same surface groundconductor 148 is provided with the slot 151 formed to be orthogonal tothe end of the high frequency line conductor 147 on the center part sideand coupled with the high frequency line conductor 147 in terms of highfrequency.

The frame ground conductor 150 is formed on the lower surface of thedielectric substrate 146 in a shape conforming to the upper side openingof the through hole 145 so as to be opposite to the end of the highfrequency line conductor 147 on the center part side. The internalground conductor 153 is formed between the high frequency line conductor147 of the inside of the dielectric substrate 146 and the frame groundconductor 150. Besides, the internal ground conductor 153 is providedwith the transmission opening 152 opposite to the slot 151 and largerthan the slot 151. The first connecting conductor 154 connects the samesurface ground conductor 148 and internal ground conductor 153. Thesecond connecting conductor 155 connects the frame ground conductor 150and the internal ground conductor 153.

The conversion substrate 156 is joined on the upper side of the throughhole 145 of the metal base 143 such that the connection terminal part149 is positioned on the side of the mounting part 142 of the metal base143 and the frame ground conductor 150 is made to conform to the upperside opening of the through hole 145 of the metal base 143.

By adopting the structure as stated above, it becomes possible toconnect the ground of the conversion substrate 156 and the ground of thehigh frequency electronic component 140 and 141 by wire bonding, and itis not necessary to provide the mounting part of the high frequencyelectronic components 140 and 141, which is formed by extending theinternal ground conductor 153 of the conversion substrate 156 to beexposed on the surface as in the related art, and the conversionsubstrate 156 can be miniaturized, and a thermal expansion mismatchbetween the conversion substrate 156 and the metal base 143 in themanufacture process of the high frequency package can be made small, sothat the warp or crack of the package can be prevented.

Besides, the connection distance between the high frequency lineconductor 147 of the conversion substrate 156 and the high frequencyline conductor of the high frequency electronic component 140 can bemade substantially equal to the connection distance between the samesurface ground conductor 148 of the conversion substrate 156 and thesame surface ground conductor of the high frequency electronic component140, and transmission becomes possible without causing a differencebetween the phase of the signal potential of the high frequency signaland the phase of the ground potential in the connection part of both,and excellent transmission of the high frequency signal becomespossible.

In this case, the dielectric waveguide part surrounded by the internalground conductor 153 and the second connection conductor 155 is shieldedby the internal ground conductor 153 from the high frequencytransmission path of the coplanar line type made of the high frequencyline conductor 147 and the same surface ground conductor 148, and theelectromagnetic resonant mode in the dielectric waveguide part isseparated from the electromagnetic transmission mode occurring in thehigh frequency transmission path. Thus, there disappears a possibilitythat the high frequency signal transmitted through the high frequencytransmission path of the coplanar line type made of the high frequencyline conductor 147 and the same surface ground conductor 148 causes anunnecessary resonance in the dielectric waveguide part surrounded by theinternal ground conductor 153 and the second connection conductor 55,and excellent conversion from the high frequency transmission path ofthe coplanar line type to the waveguide becomes possible.

Besides, in the high frequency package of the invention, when a shieldplate having, in a portion corresponding to the high frequency lineconductor of the high frequency electronic part 140, a small opening (anopening in which a cutoff frequency is higher than a signal frequency)through which an electromagnetic wave at the signal frequency can notpass is mounted on the upper surface of the high frequency electroniccomponent 140, the mount region of the conversion substrate 156 and themount region of the high frequency electronic component 141 are shieldedin high frequencies, and it is possible to provide the high frequencypackage which is excellent in isolation characteristic to an unnecessarysignal.

Besides, even in the case where the second high frequency electroniccomponent 141 without the same surface ground conductor is mounted, whena component having a same surface ground conductor, such as the highfrequency electronic component 140, is disposed between the conversionsubstrate 156 and the second high frequency component 141, and they arerespectively connected by wire bonding, it becomes possible to performexcellent transmission of a high frequency signal between the conversionsubstrate 156 and the second high frequency component 141.

Besides, in the high frequency package of the invention, when theinterval between the high frequency line conductor 147 and the samesurface ground conductor layer 148 is made ¼ or less of the signalwavelength of the high frequency signal transmitted through the highfrequency line conductor 147, in the case where the high frequency lineconductor 147 of the conversion substrate 156 and the high frequencyline conductor of the high frequency electronic component 140, and thesame surface ground conductor 148 of the conversion substrate 156 andthe same surface ground conductor of the high frequency electroniccomponent 140 are respectively connected by wire bonding, the distancebetween the wire for connecting the high frequency line conductors andthe wire for connecting the same surface ground conductors can be madeapproximately ¼ or less of the signal wavelength of the high frequencysignal, the respective wires are electromagnetically coupled to eachother to form a high frequency transmission path, and the high frequencypackage excellent in transmission of the high frequency signal can beprovided.

As a dielectric material forming the dielectric layer 106, 125 and 146,aluminum oxide, aluminum nitride, silicon nitride, ceramic materialcontaining mullite or the like as its main ingredient, glass, glassceramic material formed by firing a mixture of glass and ceramic filler,epoxy resin, polyimide resin, organic resin material such as fluorineresin including tetrafluoroethylene resin, organic resin-ceramic(including glass) composite material or the like is used.

As a conductor material forming the high frequency line conductor 107,126 and 147, the same surface ground conductor 108, 127 and 148, theframe ground conductor 110, 129 and 150, the internal ground conductor112 and 153, the first connection conductor 113 and 154, the secondconnection conductor 114 and 155 and connection conductor 131, ametalized material containing tungsten, molybdenum, gold, silver, copperor the like as its main ingredient, or a metal foil containing gold,silver, copper, aluminum or the like as its main ingredient is used.

Especially, in the case where the high frequency package contains andseals an electronic component, as the dielectric material forming thedielectric substrates 106, 125 and 146, it is desirable that thedielectric loss tangent is small and airtight sealing is possible. As anespecially desirable dielectric material, at least one kind of inorganicmaterial selected from a group consisting of aluminum oxide, aluminumnitride, and glass ceramic material can be mentioned. When such a hardmaterial is used, the dielectric loss tangent is small and the mountedhigh frequency component can be airtightly sealed, so that such amaterial is preferable in raising the reliability of the mounted highfrequency component. In this case, as a conductor material, it isdesirable in view of airtightness and productivity to use a metalizedconductor which can be fired at the same time as the dielectricmaterial.

As metal material forming the metal bases 103, 122 and 143, an alloy, acompound, a composite material or the like containing iron, cobalt,nickel, tungsten, molybdenum, copper or the like as its main ingredientis used.

The high frequency package converter of the invention is fabricated asdescribed below. For example, in the case where an aluminum oxidesintered body is used as the dielectric substrate material, first, asuitable organic solvent is added to and mixed with a raw materialpowder of aluminum oxide, silicon oxide, magnesium oxide, calcium oxideor the like to form slurry, and this is formed into a sheet by awell-known doctor blade method or a calender roll method to fabricate aceramic green sheet. Besides, a suitable organic solvent is added to andmixed with a raw material powder of high melting metal, such as tungstenor molybdenum, aluminum oxide, silicon oxide, magnesium oxide, calciumoxide or the like to fabricate a metallization paste. Next, throughholes for formation of the first connection conductor 113 and 154, thesecond connection conductor 114 and 155 and the connection conductor 131as the via hole conductor is formed in the ceramic green sheet by, forexample, a punching method, and the metallization paste is implanted inthe through holes by, for example, a printing method, and subsequently,the metallization paste is printed to have the shape of the highfrequency line conductor 107, 126 and 147, the same ground conductor108, 127 and 148, the frame ground conductor 110, 129 and 150 and theinternal ground conductor 112 and 153. In the case where the dielectricsubstrate 106, 125 and 146 is made of a laminate structure having aplurality of dielectric layers, ceramic green sheets in which theseconductors are implanted and printed are laminated, are pressurized tobe subjected to pressure bonding, and are fired at a high temperature(about 1600° C.). Further, the surfaces of the conductors exposed on thesurfaces, such as the high frequency line conductors 107, 126 and 147,the same surface ground conductors 108, 127 and 148, and the frameground conductors 110, 129 and 150, are plated with nickel or goldaccording to the subsequent assembly to form the conversion substrates115, 132 and 156.

The conversion substrates 115, 132 and 156 are joined by soldermaterial, such as silver copper solder or gold tin solder, to the upperside openings of the through holes 105, 124 and 145 to which thewaveguides 104, 123 and 144 of the metal bases 103, 122 and 143 areconnected. In the case where the solder material is the silver coppersolder, since the conversion substrates 115, 132 and 155 and the metalbases 103, 122 and 143 are joined in the state of nickel plating finish,after joining, nickel or gold plating is applied to finish up. In thecase where the solder material is the gold tin solder, since theconversion substrates 115, 132 and 156 and the metal bases 103, 122 and143 are joined in the state of nickel or gold plating finish, specificplating is not applied after the metal base joining.

In the example of the high frequency package of the invention, althoughthe case where the waveguides 104, 123 and 144 are rectangularwaveguides has been described, the shape of the waveguides 104, 123 and144 is not particularly limited, and for example, a circular waveguidemay be used.

Incidentally, the invention is not limited to the above examples of theembodiment, and various modifications may be performed within the scopeof the gist of the invention.

For example, in FIGS. 10A and 10B, although the example has beendescribed in which the end of the high frequency line conductor 107 atthe center side of the dielectric substrate 106 is opened in order toperform electromagnetic coupling of the high frequency line conductor107 and the slot 111, the end of the high frequency line conductor 107at the center side of the dielectric substrate 106 may beshort-circuited to the internal ground conductor 112 by the via holeconductor or the like in the vicinity of the slot 111 to perform theelectromagnetic coupling.

Besides, in FIGS. 11A and 11B, although the example has been describedin which the end of the high frequency line conductor 126 at the centerside of the dielectric substrate 125 is short-circuited to the slot 130in order to perform the electromagnetic coupling of the high frequencyline conductor 126 and the slot 130, the end of the high frequency lineconductor 126 at the center side of the dielectric substrate 125 may beopened as shown in FIG. 13 to perform the electromagnetic coupling.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and the rangeof equivalency of the claims are therefore intended to be embracedtherein.

1. A high frequency package comprising: a metal base having a mountingpart of a high frequency electronic component on one surface, and athrough hole disposed to be adjacent to the mounting part, an opening onone side of the through hole being connected with a waveguide; and ahigh frequency line-to-waveguide conversion substrate joined on anopening on another side of the through hole, the high frequencyline-to-waveguide conversion substrate including: a high frequency lineincluding: a dielectric substrate; a high frequency line conductordirected from an outer peripheral part to a center part on one surfaceof the dielectric substrate; and a same surface ground conductordisposed on the same surface as the one surface of the dielectricsubstrate so as to surround an end of the high frequency line conductoron the center part side, a frame ground conductor formed on anothersurface of the dielectric substrate in a shape conforming to an openingon another side of the through hole so as to be opposite to the end ofthe high frequency line conductor on the center part side; a slotprovided on the same surface ground conductor and formed to beorthogonal to the end of the high frequency line conductor on the centerpart side and coupled to the high frequency line in terms of highfrequency; and a connection conductor for connecting the same surfaceground conductor and the frame ground conductors, wherein the highfrequency line-to-waveguide conversion substrate is joined on the otherside of the through hole such that the high frequency line is positionedon a side of the mounting part and the frame ground conductor is made toconform to the opening on the other side of the through hole.
 2. Thehigh frequency package of claim 1, wherein an interval between the highfrequency line conductor and the same surface ground conductor is ¼ orless of a signal wavelength of a high frequency signal transmittedthrough the high frequency line.
 3. A high frequency package comprising:a metal base having a mounting part of a high frequency electroniccomponent on one surface, and a through hole disposed to be adjacent tothe mounting part, an opening on one side of the through hole beingconnected with a waveguide; and a high frequency line-to-waveguideconversion substrate joined on an opening on another side of the throughhole, the high frequency line-to-waveguide conversion substrateincluding: a high frequency line including: a dielectric substrate; ahigh frequency line conductor directed from an outer peripheral part toa center part on one surface of a dielectric substrate; and a samesurface ground conductor disposed on the same surface as the one surfaceof the dielectric substrate so as to surround an end of the highfrequency line conductor on the center part side, a frame groundconductor formed on another surface of the dielectric substrate in ashape conforming to an opening on another side of the through hole so asto be opposite to the end of the high frequency line conductor on thecenter part side; a slot provided on the same surface ground conductorand formed to be orthogonal to the end of the high frequency lineconductor on the center part side and coupled to the high frequency linein terms of high frequency; an internal ground conductor formed betweenthe high frequency line conductor of an inside of the dielectricsubstrate and the frame ground conductor, and provided with thetransmission opening opposite to the slot and larger than the slot; afirst connection conductor for connecting the same surface groundconductor and internal ground conductor; and a second connectionconductor for connecting the frame ground conductor and the internalground conductor, wherein the high frequency line-to-waveguideconversion substrate is jointed on the other side of the through holesuch that the high frequency line is positioned on a side of themounting part and the frame ground conductor is made to conform to theopening on the other side of the through hole.
 4. The high frequencypackage of claim 3, wherein an interval between the high frequency lineconductor and the same surface ground conductor is ¼ or less of a signalwavelength of a high frequency signal transmitted through the highfrequency line.
 5. A high frequency package comprising: a metal baseincluding a mounting part for a high frequency electric component on onesurface thereof, a through hole disposed to be adjacent to the mountingpart and having an opening on one side connected with the waveguide,being formed therein; and a conversion substrate, including: a highfrequency line including: a dielectric substrate; a high frequency lineconductor formed on one surface of the dielectric substrate and disposedso as to extend from an outer peripheral part toward a center part onthe one surface of the dielectric substrate; and a same surface groundconductor disposed on the same surface as the one surface of thedielectric substrate so as to surround an end of the high frequency lineconductor on the center part side, a frame ground conductor formed onanother surface of the dielectric substrate in a shape conforming to anopening on another side of the through hole so as to be opposite to theend of the high frequency line conductor on the center part side; a slotprovided on the same surface ground conductor and formed to beorthogonal to the end of the high frequency line conductor on the centerpart side and coupled with the high frequency line conductor in terms ofhigh frequency; and a connection conductor for connecting the samesurface ground conductor and the frame ground conductors, wherein theconversion substrate is joined on the other side of the through hole ofthe metal base such that the high frequency line is positioned on theside of the mounting part of the metal base and the frame groundconductor is made to conform to the opening on the other side of thethrough hole of the metal base.
 6. A high frequency package comprising:a metal base including a mounting part for a high frequency electriccomponent at one surface thereof, the through hole disposed to beadjacent to the mounting part and having an opening on one side thereofconnected with the waveguide, being formed therein; and a conversionsubstrate including: a high frequency line including: a dielectricsubstrate; a high frequency line conductor disposed so as to extend froman outer peripheral part toward a center part on one surface of thedielectric substrate; and a same surface ground conductor disposed onthe same surface as the one surface of the dielectric substrate so as tosurround an end of the high frequency line conductor on the center partside, a frame ground conductor formed on another surface of thedielectric substrate in a shape conforming to an opening on another sideof the through hole so as to be opposite to the end of the highfrequency line conductor on the center part side; a slot provided on thesame surface ground conductor and formed to be orthogonal to the end ofthe high frequency line conductor on the center part side and coupledwith the high frequency line conductor in terms of high frequency; aninternal ground conductor formed between the high frequency lineconductor of an inside of the dielectric substrate and the frame groundconductor, and provided with the transmission opening opposite to theslot and larger than the slot; a first connection conductor forconnecting the same surface ground conductor and internal groundconductor; and a second connection conductor for connecting the frameground conductor and the internal ground conductor, wherein theconversion substrate is joined on the other side of the through hole ofthe metal base such that the high frequency line is positioned on theside of the mounting part of the metal base and the frame groundconductor is made to conform to the opening on the other side of thethrough hole of the metal base.